diff --git a/core/base/src/main/res/values/strings.xml b/core/base/src/main/res/values/strings.xml
index 1144d3c6..de34f1ce 100644
--- a/core/base/src/main/res/values/strings.xml
+++ b/core/base/src/main/res/values/strings.xml
@@ -81,6 +81,12 @@ Used in this dialog window. Should be short -->
     <string name="select_time_label">Select time</string>
     <string name="settings_about_unitto">About Unitto</string>
     <string name="settings_about_unitto_support">Learn about the app</string>
+
+    <!-- https://s3.eu-west-1.amazonaws.com/po-pub/i/p3aY3IWUI5m9Vjs6vZP3EXAo.png -->
+    <string name="settings_ac_button">AC button</string>
+
+    <!-- https://s3.eu-west-1.amazonaws.com/po-pub/i/p3aY3IWUI5m9Vjs6vZP3EXAo.png -->
+    <string name="settings_ac_button_support">Show separate clear button</string>
     <string name="settings_additional">Additional</string>
     <string name="settings_amoled_dark">AMOLED Dark</string>
     <string name="settings_amoled_dark_support">Use black background for dark themes</string>
diff --git a/core/ui/src/main/java/com/sadellie/unitto/core/ui/common/KeyboardButton.kt b/core/ui/src/main/java/com/sadellie/unitto/core/ui/common/KeyboardButton.kt
index e76a4e6b..a77994a7 100644
--- a/core/ui/src/main/java/com/sadellie/unitto/core/ui/common/KeyboardButton.kt
+++ b/core/ui/src/main/java/com/sadellie/unitto/core/ui/common/KeyboardButton.kt
@@ -140,3 +140,24 @@ fun KeyboardButtonAdditional(
         allowVibration = allowVibration,
     )
 }
+
+@Composable
+fun KeyboardButtonTertiary(
+    modifier: Modifier,
+    icon: ImageVector,
+    allowVibration: Boolean,
+    contentHeight: Float = if (isPortrait()) 0.578f else 0.793f,
+    onLongClick: (() -> Unit)? = null,
+    onClick: () -> Unit,
+) {
+    BasicKeyboardButton(
+        modifier = modifier,
+        contentHeight = contentHeight,
+        onClick = onClick,
+        onLongClick = onLongClick,
+        containerColor = MaterialTheme.colorScheme.tertiaryContainer,
+        icon = icon,
+        iconColor = MaterialTheme.colorScheme.onTertiaryContainer,
+        allowVibration = allowVibration,
+    )
+}
diff --git a/core/ui/src/main/java/com/sadellie/unitto/core/ui/common/textfield/CursorFixer.kt b/core/ui/src/main/java/com/sadellie/unitto/core/ui/common/textfield/CursorFixer.kt
index acbd5134..010f8876 100644
--- a/core/ui/src/main/java/com/sadellie/unitto/core/ui/common/textfield/CursorFixer.kt
+++ b/core/ui/src/main/java/com/sadellie/unitto/core/ui/common/textfield/CursorFixer.kt
@@ -85,14 +85,14 @@ private fun Int.isAfterToken(str: String, token: String): Boolean {
 }
 
 
-// This can make [TextFieldValue.addTokens] better by checking tokens both ways. Needs more tests
-//fun String.tokenAfter(pos: Int): String {
-//    Token.Func.allWithOpeningBracket.forEach {
-//        if (pos.isBeforeToken(this, it)) return it
-//    }
-//
-//    return substring(pos, (pos + 1).coerceAtMost(this.length))
-//}
+// This can also make [TextFieldValue.addTokens] better by checking tokens both ways. Needs more tests
+fun String.tokenAfter(pos: Int): String {
+    Token.Func.allWithOpeningBracket.forEach {
+        if (pos.isBeforeToken(this, it)) return it
+    }
+
+    return substring(pos, (pos + 1).coerceAtMost(this.length))
+}
 
 //private fun String.numberNearby(cursor: Int): String {
 //    val text = this
@@ -111,8 +111,8 @@ private fun Int.isAfterToken(str: String, token: String): Boolean {
 //    return text.substring(aheadCursor, afterCursor)
 //}
 
-//private fun Int.isBeforeToken(str: String, token: String): Boolean {
-//    return str
-//        .substring(this, (this + token.length).coerceAtMost(str.length))
-//        .contains(token)
-//}
+private fun Int.isBeforeToken(str: String, token: String): Boolean {
+    return str
+        .substring(this, (this + token.length).coerceAtMost(str.length))
+        .contains(token)
+}
diff --git a/core/ui/src/main/java/com/sadellie/unitto/core/ui/common/textfield/TextFieldValueExtensions.kt b/core/ui/src/main/java/com/sadellie/unitto/core/ui/common/textfield/TextFieldValueExtensions.kt
index d97b1e8b..3df15e5b 100644
--- a/core/ui/src/main/java/com/sadellie/unitto/core/ui/common/textfield/TextFieldValueExtensions.kt
+++ b/core/ui/src/main/java/com/sadellie/unitto/core/ui/common/textfield/TextFieldValueExtensions.kt
@@ -53,15 +53,52 @@ fun TextFieldValue.addTokens(tokens: String): TextFieldValue {
     )
 }
 
-/**
- * <b>!!! Recursive !!!</b> (one wrong step and you are dead 💀)
- */
-private fun TextFieldValue.deleteAheadAndAdd(tokens: String): TextFieldValue {
-    var newValue = this
-    if (!selection.collapsed) newValue = this.deleteTokens()
-    return newValue
-        .deleteTokens()
-        .addTokens(tokens)
+fun TextFieldValue.addBracket(): TextFieldValue {
+    val subStringBeforeCursor = text.substring(0..<selection.start)
+
+    // Always open when empty in front
+    if (subStringBeforeCursor.isEmpty()) {
+        return addTokens(Token.Operator.leftBracket)
+    }
+
+    // Always close before operator
+    val operators = listOf(
+        Token.Operator.multiply,
+        Token.Operator.divide,
+        Token.Operator.plus,
+        Token.Operator.minus,
+        Token.Operator.power,
+    )
+    if (text.tokenAfter(selection.start) in operators) {
+        return addTokens(Token.Operator.rightBracket)
+    }
+
+    // Always open when balanced in front
+    val leftBracketChar: Char = Token.Operator.leftBracket.first()
+    val rightBracketChar: Char = Token.Operator.rightBracket.first()
+    var balance = 0
+    subStringBeforeCursor.forEach {
+        if (it == leftBracketChar) balance += 1
+        if (it == rightBracketChar) balance -= 1
+    }
+    if (balance == 0) {
+        return addTokens(Token.Operator.leftBracket)
+    }
+
+    // Always open after operator
+    val operators2 = listOf(
+        Token.Operator.multiply,
+        Token.Operator.divide,
+        Token.Operator.plus,
+        Token.Operator.minus,
+        Token.Operator.power,
+        Token.Operator.leftBracket
+    )
+    if (text.tokenAhead(selection.start) in operators2) {
+        return addTokens(Token.Operator.leftBracket)
+    }
+
+    return addTokens(Token.Operator.rightBracket)
 }
 
 fun TextFieldValue.deleteTokens(): TextFieldValue {
@@ -93,3 +130,14 @@ fun TextFieldValue.deleteTokens(): TextFieldValue {
         selection = TextRange((newText.length - distanceFromEnd).coerceAtLeast(0))
     )
 }
+
+/**
+ * <b>!!! Recursive !!!</b> (one wrong step and you are dead 💀)
+ */
+private fun TextFieldValue.deleteAheadAndAdd(tokens: String): TextFieldValue {
+    var newValue = this
+    if (!selection.collapsed) newValue = this.deleteTokens()
+    return newValue
+        .deleteTokens()
+        .addTokens(tokens)
+}
diff --git a/core/ui/src/test/java/com/sadellie/unitto/core/ui/TextFieldValueExtensionsTest.kt b/core/ui/src/test/java/com/sadellie/unitto/core/ui/TextFieldValueExtensionsTest.kt
index 4c419be3..8e350164 100644
--- a/core/ui/src/test/java/com/sadellie/unitto/core/ui/TextFieldValueExtensionsTest.kt
+++ b/core/ui/src/test/java/com/sadellie/unitto/core/ui/TextFieldValueExtensionsTest.kt
@@ -21,6 +21,7 @@ package com.sadellie.unitto.core.ui
 import androidx.compose.ui.text.TextRange
 import androidx.compose.ui.text.input.TextFieldValue
 import com.sadellie.unitto.core.base.Token
+import com.sadellie.unitto.core.ui.common.textfield.addBracket
 import com.sadellie.unitto.core.ui.common.textfield.addTokens
 import org.junit.Assert.assertEquals
 import org.junit.Test
@@ -260,6 +261,60 @@ class TextFieldValueExtensionsTest {
         assertEquals(tf("123+45.[]78"), tf("123+45[6.]78").addTokens(Token.Digit.dot))
     }
 
+    @Test
+    fun auto() {
+        // Open on empty in front
+        assertEquals(tf("([]"), tf("[]").addBracket())
+        assertEquals(tf("([]123("), tf("[]123(").addBracket())
+        assertEquals(tf("([]("), tf("[123](").addBracket())
+        assertEquals(tf("([]"), tf("[123(]").addBracket())
+
+        // Close before multiply
+        assertEquals(tf("123)[]*456"), tf("123[]*456").addBracket())
+        assertEquals(tf("(123)[]*456"), tf("(123[]*456").addBracket())
+        assertEquals(tf(")123)[]*456"), tf(")123[]*456").addBracket())
+        // Close before divide
+        assertEquals(tf("123)[]/456"), tf("123[]/456").addBracket())
+        assertEquals(tf("(123)[]/456"), tf("(123[]/456").addBracket())
+        assertEquals(tf(")123)[]/456"), tf(")123[]/456").addBracket())
+        // Close before plus
+        assertEquals(tf("123)[]+456"), tf("123[]+456").addBracket())
+        assertEquals(tf("(123)[]+456"), tf("(123[]+456").addBracket())
+        assertEquals(tf(")123)[]+456"), tf(")123[]+456").addBracket())
+        // Close before minus
+        assertEquals(tf("123)[]-456"), tf("123[]-456").addBracket())
+        assertEquals(tf("(123)[]-456"), tf("(123[]-456").addBracket())
+        assertEquals(tf(")123)[]-456"), tf(")123[]-456").addBracket())
+        // Close before power
+        assertEquals(tf("123)[]^456"), tf("123[]^456").addBracket())
+        assertEquals(tf("(123)[]^456"), tf("(123[]^456").addBracket())
+        assertEquals(tf(")123)[]^456"), tf(")123[]^456").addBracket())
+
+        // Open on balanced in front
+        assertEquals(tf("123([]"), tf("123[]").addBracket())
+        assertEquals(tf("123([](((("), tf("123[]((((").addBracket())
+
+        // Open after multiply
+        assertEquals(tf("123*([]456"), tf("123*[]456").addBracket())
+        assertEquals(tf("123*([]"), tf("123*[456]").addBracket())
+        // Open after divide
+        assertEquals(tf("123/([]456"), tf("123/[]456").addBracket())
+        assertEquals(tf("123/([]"), tf("123/[456]").addBracket())
+        // Open after plus
+        assertEquals(tf("123+([]456"), tf("123+[]456").addBracket())
+        assertEquals(tf("123+([]"), tf("123+[456]").addBracket())
+        // Open after minus
+        assertEquals(tf("123-([]456"), tf("123-[]456").addBracket())
+        assertEquals(tf("123-([]"), tf("123-[456]").addBracket())
+        // Open after power
+        assertEquals(tf("123^([]456"), tf("123^[]456").addBracket())
+        assertEquals(tf("123^([]"), tf("123^[456]").addBracket())
+
+        // Default
+        assertEquals(tf("123([]"), tf("123[]").addBracket())
+        assertEquals(tf("123(456+789)[]"), tf("123(456+789[]").addBracket())
+    }
+
     // Use [] for selection
     private fun tf(
         text: String = "",
@@ -267,6 +322,9 @@ class TextFieldValueExtensionsTest {
         val selectionStart = text.indexOf("[")
         val selectionEnd = text.indexOf("]") - 1
 
+        if (selectionStart < 0) throw Exception("forgot selectionStart")
+        if (selectionEnd < 0) throw Exception("forgot selectionEnd")
+
         return TextFieldValue(
             text = text
                 .replace("[", "")
diff --git a/data/userprefs/src/main/java/com/sadellie/unitto/data/userprefs/PreferenceModels.kt b/data/userprefs/src/main/java/com/sadellie/unitto/data/userprefs/PreferenceModels.kt
index 9a0ecb47..cf45c596 100644
--- a/data/userprefs/src/main/java/com/sadellie/unitto/data/userprefs/PreferenceModels.kt
+++ b/data/userprefs/src/main/java/com/sadellie/unitto/data/userprefs/PreferenceModels.kt
@@ -45,6 +45,7 @@ data class CalculatorPreferences(
     val enableVibrations: Boolean,
     val separator: Int,
     val middleZero: Boolean,
+    val acButton: Boolean,
     val partialHistoryView: Boolean,
     val precision: Int,
     val outputFormat: Int,
@@ -54,6 +55,7 @@ data class ConverterPreferences(
     val enableVibrations: Boolean,
     val separator: Int,
     val middleZero: Boolean,
+    val acButton: Boolean,
     val precision: Int,
     val outputFormat: Int,
     val unitConverterFormatTime: Boolean,
@@ -68,6 +70,7 @@ data class ConverterPreferences(
 data class DisplayPreferences(
     val systemFont: Boolean,
     val middleZero: Boolean,
+    val acButton: Boolean,
 )
 
 data class FormattingPreferences(
diff --git a/data/userprefs/src/main/java/com/sadellie/unitto/data/userprefs/PrefsKeys.kt b/data/userprefs/src/main/java/com/sadellie/unitto/data/userprefs/PrefsKeys.kt
index 36a4a18f..156a6c44 100644
--- a/data/userprefs/src/main/java/com/sadellie/unitto/data/userprefs/PrefsKeys.kt
+++ b/data/userprefs/src/main/java/com/sadellie/unitto/data/userprefs/PrefsKeys.kt
@@ -46,4 +46,5 @@ internal object PrefsKeys {
     val MIDDLE_ZERO = booleanPreferencesKey("MIDDLE_ZERO_PREF_KEY")
     val SYSTEM_FONT = booleanPreferencesKey("SYSTEM_FONT_PREF_KEY")
     val PARTIAL_HISTORY_VIEW = booleanPreferencesKey("PARTIAL_HISTORY_VIEW_PREF_KEY")
+    val AC_BUTTON = booleanPreferencesKey("AC_BUTTON_PREF_KEY")
 }
diff --git a/data/userprefs/src/main/java/com/sadellie/unitto/data/userprefs/UserPreferences.kt b/data/userprefs/src/main/java/com/sadellie/unitto/data/userprefs/UserPreferences.kt
index a988391d..45912ddb 100644
--- a/data/userprefs/src/main/java/com/sadellie/unitto/data/userprefs/UserPreferences.kt
+++ b/data/userprefs/src/main/java/com/sadellie/unitto/data/userprefs/UserPreferences.kt
@@ -75,7 +75,8 @@ class UserPreferencesRepository @Inject constructor(
                 middleZero = preferences.getMiddleZero(),
                 partialHistoryView = preferences.getPartialHistoryView(),
                 precision = preferences.getDigitsPrecision(),
-                outputFormat = preferences.getOutputFormat()
+                outputFormat = preferences.getOutputFormat(),
+                acButton = preferences.getAcButton(),
             )
         }
 
@@ -94,6 +95,7 @@ class UserPreferencesRepository @Inject constructor(
                 enableToolsExperiment = preferences.getEnableToolsExperiment(),
                 latestLeftSideUnit = preferences.getLatestLeftSide(),
                 latestRightSideUnit = preferences.getLatestRightSide(),
+                acButton = preferences.getAcButton(),
             )
         }
 
@@ -102,6 +104,7 @@ class UserPreferencesRepository @Inject constructor(
             DisplayPreferences(
                 systemFont = preferences.getSystemFont(),
                 middleZero = preferences.getMiddleZero(),
+                acButton = preferences.getAcButton(),
             )
         }
 
@@ -263,6 +266,12 @@ class UserPreferencesRepository @Inject constructor(
             preferences[PrefsKeys.PARTIAL_HISTORY_VIEW] = enabled
         }
     }
+
+    suspend fun updateAcButton(enabled: Boolean) {
+        dataStore.edit { preferences ->
+            preferences[PrefsKeys.AC_BUTTON] = enabled
+        }
+    }
 }
 
 private fun Preferences.getEnableDynamicTheme(): Boolean {
@@ -359,6 +368,10 @@ private fun Preferences.getLatestRightSide(): String {
     return this[PrefsKeys.LATEST_RIGHT_SIDE] ?: MyUnitIDS.mile
 }
 
+private fun Preferences.getAcButton(): Boolean {
+    return this[PrefsKeys.AC_BUTTON] ?: false
+}
+
 private inline fun <T, R> T.letTryOrNull(block: (T) -> R): R? = try {
     this?.let(block)
 } catch (e: Exception) {
diff --git a/feature/calculator/src/main/java/com/sadellie/unitto/feature/calculator/CalculatorScreen.kt b/feature/calculator/src/main/java/com/sadellie/unitto/feature/calculator/CalculatorScreen.kt
index 20484ca3..2fa0d461 100644
--- a/feature/calculator/src/main/java/com/sadellie/unitto/feature/calculator/CalculatorScreen.kt
+++ b/feature/calculator/src/main/java/com/sadellie/unitto/feature/calculator/CalculatorScreen.kt
@@ -89,7 +89,8 @@ internal fun CalculatorRoute(
         onCursorChange = viewModel::onCursorChange,
         toggleCalculatorMode = viewModel::toggleCalculatorMode,
         evaluate = viewModel::evaluate,
-        clearHistory = viewModel::clearHistory
+        clearHistory = viewModel::clearHistory,
+        addBracket = viewModel::addBracket
     )
 }
 
@@ -99,6 +100,7 @@ internal fun CalculatorScreen(
     navigateToMenu: () -> Unit,
     navigateToSettings: () -> Unit,
     addTokens: (String) -> Unit,
+    addBracket: () -> Unit,
     clearInput: () -> Unit,
     deleteTokens: () -> Unit,
     onCursorChange: (TextRange) -> Unit,
@@ -118,7 +120,8 @@ internal fun CalculatorScreen(
             onCursorChange = onCursorChange,
             toggleAngleMode = toggleCalculatorMode,
             evaluate = evaluate,
-            clearHistory = clearHistory
+            clearHistory = clearHistory,
+            addBracket = addBracket
         )
     }
 }
@@ -129,6 +132,7 @@ private fun Ready(
     navigateToMenu: () -> Unit,
     navigateToSettings: () -> Unit,
     addSymbol: (String) -> Unit,
+    addBracket: () -> Unit,
     clearSymbols: () -> Unit,
     deleteSymbol: () -> Unit,
     onCursorChange: (TextRange) -> Unit,
@@ -264,6 +268,8 @@ private fun Ready(
                 toggleAngleMode = toggleAngleMode,
                 evaluate = evaluate,
                 middleZero = uiState.middleZero,
+                acButton = uiState.acButton,
+                addBracket = addBracket
             )
         }
     }
@@ -343,6 +349,7 @@ private fun PreviewCalculatorScreen() {
         onCursorChange = {},
         toggleCalculatorMode = {},
         evaluate = {},
-        clearHistory = {}
+        clearHistory = {},
+        addBracket = {}
     )
 }
\ No newline at end of file
diff --git a/feature/calculator/src/main/java/com/sadellie/unitto/feature/calculator/CalculatorUIState.kt b/feature/calculator/src/main/java/com/sadellie/unitto/feature/calculator/CalculatorUIState.kt
index c1fc01eb..862d4b7a 100644
--- a/feature/calculator/src/main/java/com/sadellie/unitto/feature/calculator/CalculatorUIState.kt
+++ b/feature/calculator/src/main/java/com/sadellie/unitto/feature/calculator/CalculatorUIState.kt
@@ -35,6 +35,7 @@ internal sealed class CalculatorUIState {
         val allowVibration: Boolean = false,
         val formatterSymbols: FormatterSymbols = FormatterSymbols.Spaces,
         val middleZero: Boolean = false,
+        val acButton: Boolean = false,
         val partialHistoryView: Boolean = true,
     ) : CalculatorUIState()
 }
diff --git a/feature/calculator/src/main/java/com/sadellie/unitto/feature/calculator/CalculatorViewModel.kt b/feature/calculator/src/main/java/com/sadellie/unitto/feature/calculator/CalculatorViewModel.kt
index e4816934..6cc81be5 100644
--- a/feature/calculator/src/main/java/com/sadellie/unitto/feature/calculator/CalculatorViewModel.kt
+++ b/feature/calculator/src/main/java/com/sadellie/unitto/feature/calculator/CalculatorViewModel.kt
@@ -26,6 +26,7 @@ import com.sadellie.unitto.core.base.OutputFormat
 import com.sadellie.unitto.core.base.Separator
 import com.sadellie.unitto.core.base.Token
 import com.sadellie.unitto.core.ui.common.textfield.AllFormatterSymbols
+import com.sadellie.unitto.core.ui.common.textfield.addBracket
 import com.sadellie.unitto.core.ui.common.textfield.addTokens
 import com.sadellie.unitto.core.ui.common.textfield.deleteTokens
 import com.sadellie.unitto.data.calculator.CalculatorHistoryRepository
@@ -67,7 +68,8 @@ internal class CalculatorViewModel @Inject constructor(
                 middleZero = false,
                 partialHistoryView = true,
                 precision = 3,
-                outputFormat = OutputFormat.PLAIN
+                outputFormat = OutputFormat.PLAIN,
+                acButton = false,
             )
         )
 
@@ -87,6 +89,7 @@ internal class CalculatorViewModel @Inject constructor(
             allowVibration = userPrefs.enableVibrations,
             formatterSymbols = AllFormatterSymbols.getById(userPrefs.separator),
             middleZero = userPrefs.middleZero,
+            acButton = userPrefs.acButton,
             partialHistoryView = userPrefs.partialHistoryView,
         )
     }
@@ -95,6 +98,7 @@ internal class CalculatorViewModel @Inject constructor(
     )
 
     fun addTokens(tokens: String) = _input.update { it.addTokens(tokens) }
+    fun addBracket() = _input.update { it.addBracket() }
     fun deleteTokens() = _input.update { it.deleteTokens() }
     fun clearInput() = _input.update { TextFieldValue() }
     fun onCursorChange(selection: TextRange) = _input.update { it.copy(selection = selection) }
diff --git a/feature/calculator/src/main/java/com/sadellie/unitto/feature/calculator/components/CalculatorKeyboard.kt b/feature/calculator/src/main/java/com/sadellie/unitto/feature/calculator/components/CalculatorKeyboard.kt
index 69f11377..b3475eb5 100644
--- a/feature/calculator/src/main/java/com/sadellie/unitto/feature/calculator/components/CalculatorKeyboard.kt
+++ b/feature/calculator/src/main/java/com/sadellie/unitto/feature/calculator/components/CalculatorKeyboard.kt
@@ -56,12 +56,15 @@ import com.sadellie.unitto.core.ui.common.ColumnWithConstraints
 import com.sadellie.unitto.core.ui.common.KeyboardButtonAdditional
 import com.sadellie.unitto.core.ui.common.KeyboardButtonFilled
 import com.sadellie.unitto.core.ui.common.KeyboardButtonLight
+import com.sadellie.unitto.core.ui.common.KeyboardButtonTertiary
 import com.sadellie.unitto.core.ui.common.RowWithConstraints
 import com.sadellie.unitto.core.ui.common.key.UnittoIcons
 import com.sadellie.unitto.core.ui.common.key.unittoicons.AcTan
 import com.sadellie.unitto.core.ui.common.key.unittoicons.ArCos
 import com.sadellie.unitto.core.ui.common.key.unittoicons.ArSin
 import com.sadellie.unitto.core.ui.common.key.unittoicons.Backspace
+import com.sadellie.unitto.core.ui.common.key.unittoicons.Brackets
+import com.sadellie.unitto.core.ui.common.key.unittoicons.Clear
 import com.sadellie.unitto.core.ui.common.key.unittoicons.Comma
 import com.sadellie.unitto.core.ui.common.key.unittoicons.Cos
 import com.sadellie.unitto.core.ui.common.key.unittoicons.Deg
@@ -106,7 +109,9 @@ internal fun CalculatorKeyboard(
     fractional: String,
     allowVibration: Boolean,
     middleZero: Boolean,
+    acButton: Boolean,
     addSymbol: (String) -> Unit,
+    addBracket: () -> Unit,
     clearSymbols: () -> Unit,
     deleteSymbol: () -> Unit,
     toggleAngleMode: () -> Unit,
@@ -123,7 +128,9 @@ internal fun CalculatorKeyboard(
             toggleAngleMode = toggleAngleMode,
             deleteSymbol = deleteSymbol,
             clearSymbols = clearSymbols,
-            evaluate = evaluate
+            evaluate = evaluate,
+            acButton = acButton,
+            addBracket = addBracket,
         )
     } else {
         LandscapeKeyboard(
@@ -136,7 +143,9 @@ internal fun CalculatorKeyboard(
             toggleAngleMode = toggleAngleMode,
             deleteSymbol = deleteSymbol,
             clearSymbols = clearSymbols,
-            evaluate = evaluate
+            evaluate = evaluate,
+            acButton = acButton,
+            addBracket = addBracket,
         )
     }
 }
@@ -152,7 +161,9 @@ private fun PortraitKeyboard(
     toggleAngleMode: () -> Unit,
     deleteSymbol: () -> Unit,
     clearSymbols: () -> Unit,
-    evaluate: () -> Unit
+    evaluate: () -> Unit,
+    acButton: Boolean,
+    addBracket: () -> Unit,
 ) {
     val fractionalIcon = remember { if (fractional == Token.Digit.dot) UnittoIcons.Dot else UnittoIcons.Comma }
     var showAdditional: Boolean by remember { mutableStateOf(false) }
@@ -239,8 +250,13 @@ private fun PortraitKeyboard(
         Spacer(modifier = Modifier.height(spacerHeight))
 
         Row(weightModifier) {
-            KeyboardButtonFilled(mainButtonModifier, UnittoIcons.LeftBracket, allowVibration) { addSymbol(Token.Operator.leftBracket) }
-            KeyboardButtonFilled(mainButtonModifier, UnittoIcons.RightBracket, allowVibration) { addSymbol(Token.Operator.rightBracket) }
+            if (acButton) {
+                KeyboardButtonTertiary(mainButtonModifier, UnittoIcons.Clear, allowVibration) { clearSymbols() }
+                KeyboardButtonFilled(mainButtonModifier, UnittoIcons.Brackets, allowVibration) { addBracket() }
+            } else {
+                KeyboardButtonFilled(mainButtonModifier, UnittoIcons.LeftBracket, allowVibration) { addSymbol(Token.Operator.leftBracket) }
+                KeyboardButtonFilled(mainButtonModifier, UnittoIcons.RightBracket, allowVibration) { addSymbol(Token.Operator.rightBracket) }
+            }
             KeyboardButtonFilled(mainButtonModifier, UnittoIcons.Percent, allowVibration) { addSymbol(Token.Operator.percent) }
             KeyboardButtonFilled(mainButtonModifier, UnittoIcons.Divide, allowVibration) { addSymbol(Token.Operator.divide) }
         }
@@ -361,7 +377,9 @@ private fun LandscapeKeyboard(
     toggleAngleMode: () -> Unit,
     deleteSymbol: () -> Unit,
     clearSymbols: () -> Unit,
-    evaluate: () -> Unit
+    evaluate: () -> Unit,
+    acButton: Boolean,
+    addBracket: () -> Unit,
 ) {
     val fractionalIcon = remember { if (fractional == Token.Digit.dot) UnittoIcons.Dot else UnittoIcons.Comma }
     var invMode: Boolean by remember { mutableStateOf(false) }
@@ -426,13 +444,21 @@ private fun LandscapeKeyboard(
         }
 
         Column(Modifier.weight(1f)) {
-            KeyboardButtonFilled(buttonModifier, UnittoIcons.LeftBracket, allowVibration) { addSymbol(Token.Operator.leftBracket) }
+            if (acButton) {
+                KeyboardButtonTertiary(buttonModifier, UnittoIcons.Clear, allowVibration) { clearSymbols() }
+            } else {
+                KeyboardButtonFilled(buttonModifier, UnittoIcons.LeftBracket, allowVibration) { addSymbol(Token.Operator.leftBracket) }
+            }
             KeyboardButtonFilled(buttonModifier, UnittoIcons.Multiply, allowVibration) { addSymbol(Token.Operator.multiply) }
             KeyboardButtonFilled(buttonModifier, UnittoIcons.Minus, allowVibration) { addSymbol(Token.Operator.minus) }
             KeyboardButtonFilled(buttonModifier, UnittoIcons.Plus, allowVibration) { addSymbol(Token.Operator.plus) }
         }
         Column(Modifier.weight(1f)) {
-            KeyboardButtonFilled(buttonModifier, UnittoIcons.RightBracket, allowVibration) { addSymbol(Token.Operator.rightBracket) }
+            if (acButton) {
+                KeyboardButtonTertiary(buttonModifier, UnittoIcons.Brackets, allowVibration) { addBracket() }
+            } else {
+                KeyboardButtonFilled(buttonModifier, UnittoIcons.RightBracket, allowVibration) { addSymbol(Token.Operator.rightBracket) }
+            }
             KeyboardButtonFilled(buttonModifier, UnittoIcons.Divide, allowVibration) { addSymbol(Token.Operator.divide) }
             KeyboardButtonFilled(buttonModifier, UnittoIcons.Percent, allowVibration) { addSymbol(Token.Operator.percent) }
             KeyboardButtonFilled(buttonModifier, UnittoIcons.Equal, allowVibration) { evaluate() }
@@ -518,5 +544,7 @@ private fun PreviewCalculatorKeyboard() {
         evaluate = {},
         allowVibration = false,
         middleZero = false,
+        acButton = true,
+        addBracket = {}
     )
 }
diff --git a/feature/converter/src/main/java/com/sadellie/unitto/feature/converter/ConverterScreen.kt b/feature/converter/src/main/java/com/sadellie/unitto/feature/converter/ConverterScreen.kt
index 8a675cd7..de4709fd 100644
--- a/feature/converter/src/main/java/com/sadellie/unitto/feature/converter/ConverterScreen.kt
+++ b/feature/converter/src/main/java/com/sadellie/unitto/feature/converter/ConverterScreen.kt
@@ -110,6 +110,7 @@ internal fun ConverterRoute(
         clearInput = viewModel::clearInput,
         onCursorChange = viewModel::onCursorChange,
         onErrorClick = viewModel::updateCurrencyRates,
+        addBracket = viewModel::addBracket
     )
 }
 
@@ -126,6 +127,7 @@ private fun ConverterScreen(
     clearInput: () -> Unit,
     onCursorChange: (TextRange) -> Unit,
     onErrorClick: (AbstractUnit) -> Unit,
+    addBracket: () -> Unit,
 ) {
     when (uiState) {
         UnitConverterUIState.Loading -> UnittoEmptyScreen()
@@ -164,7 +166,8 @@ private fun ConverterScreen(
                     swapUnits = swapUnits,
                     navigateToRightScreen = navigateToRightScreen,
                     clearInput = clearInput,
-                    refreshCurrencyRates = onErrorClick
+                    refreshCurrencyRates = onErrorClick,
+                    addBracket = addBracket,
                 )
             }
         }
@@ -258,6 +261,7 @@ private fun Default(
     navigateToRightScreen: () -> Unit,
     clearInput: () -> Unit,
     refreshCurrencyRates: (AbstractUnit) -> Unit,
+    addBracket: () -> Unit,
 ) {
     val locale: Locale = LocalLocale.current
     var calculation by remember(uiState.calculation) {
@@ -365,7 +369,9 @@ private fun Default(
                 clearInput = clearInput,
                 allowVibration = uiState.enableHaptic,
                 fractional = uiState.formatterSymbols.fractional,
-                middleZero = uiState.middleZero
+                middleZero = uiState.middleZero,
+                acButton = uiState.acButton,
+                addBracket = addBracket
             )
         }
     )
@@ -522,5 +528,6 @@ private fun PreviewConverterScreen() {
         clearInput = {},
         onCursorChange = {},
         onErrorClick = {},
+        addBracket = {}
     )
 }
diff --git a/feature/converter/src/main/java/com/sadellie/unitto/feature/converter/ConverterUIState.kt b/feature/converter/src/main/java/com/sadellie/unitto/feature/converter/ConverterUIState.kt
index e264d76e..cd91c026 100644
--- a/feature/converter/src/main/java/com/sadellie/unitto/feature/converter/ConverterUIState.kt
+++ b/feature/converter/src/main/java/com/sadellie/unitto/feature/converter/ConverterUIState.kt
@@ -46,6 +46,7 @@ internal sealed class UnitConverterUIState {
         val outputFormat: Int,
         val formatTime: Boolean,
         val currencyRateUpdateState: CurrencyRateUpdateState,
+        val acButton: Boolean,
     ) : UnitConverterUIState()
 
     data class NumberBase(
diff --git a/feature/converter/src/main/java/com/sadellie/unitto/feature/converter/ConverterViewModel.kt b/feature/converter/src/main/java/com/sadellie/unitto/feature/converter/ConverterViewModel.kt
index edc214ab..f07cc8f1 100644
--- a/feature/converter/src/main/java/com/sadellie/unitto/feature/converter/ConverterViewModel.kt
+++ b/feature/converter/src/main/java/com/sadellie/unitto/feature/converter/ConverterViewModel.kt
@@ -25,6 +25,7 @@ import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import com.sadellie.unitto.core.base.Token
 import com.sadellie.unitto.core.ui.common.textfield.AllFormatterSymbols
+import com.sadellie.unitto.core.ui.common.textfield.addBracket
 import com.sadellie.unitto.core.ui.common.textfield.addTokens
 import com.sadellie.unitto.core.ui.common.textfield.deleteTokens
 import com.sadellie.unitto.data.common.combine
@@ -105,7 +106,8 @@ internal class ConverterViewModel @Inject constructor(
                     scale = prefs.precision,
                     outputFormat = prefs.outputFormat,
                     formatTime = prefs.unitConverterFormatTime,
-                    currencyRateUpdateState = currenciesState
+                    currencyRateUpdateState = currenciesState,
+                    acButton = prefs.acButton,
                 )
             }
             (unitFrom is NumberBaseUnit) and (unitTo is NumberBaseUnit) -> {
@@ -256,6 +258,12 @@ internal class ConverterViewModel @Inject constructor(
         newValue
     }
 
+    fun addBracket() = _input.update {
+        val newValue = it.addBracket()
+        savedStateHandle[converterInputKey] = newValue.text
+        newValue
+    }
+
     fun deleteTokens() = _input.update {
         val newValue = it.deleteTokens()
         savedStateHandle[converterInputKey] = newValue.text
diff --git a/feature/converter/src/main/java/com/sadellie/unitto/feature/converter/components/ConverterKeyboard.kt b/feature/converter/src/main/java/com/sadellie/unitto/feature/converter/components/ConverterKeyboard.kt
index b859ae97..b64df4f1 100644
--- a/feature/converter/src/main/java/com/sadellie/unitto/feature/converter/components/ConverterKeyboard.kt
+++ b/feature/converter/src/main/java/com/sadellie/unitto/feature/converter/components/ConverterKeyboard.kt
@@ -31,8 +31,11 @@ import com.sadellie.unitto.core.base.Token
 import com.sadellie.unitto.core.ui.common.ColumnWithConstraints
 import com.sadellie.unitto.core.ui.common.KeyboardButtonFilled
 import com.sadellie.unitto.core.ui.common.KeyboardButtonLight
+import com.sadellie.unitto.core.ui.common.KeyboardButtonTertiary
 import com.sadellie.unitto.core.ui.common.key.UnittoIcons
 import com.sadellie.unitto.core.ui.common.key.unittoicons.Backspace
+import com.sadellie.unitto.core.ui.common.key.unittoicons.Brackets
+import com.sadellie.unitto.core.ui.common.key.unittoicons.Clear
 import com.sadellie.unitto.core.ui.common.key.unittoicons.Comma
 import com.sadellie.unitto.core.ui.common.key.unittoicons.Divide
 import com.sadellie.unitto.core.ui.common.key.unittoicons.Dot
@@ -70,6 +73,8 @@ internal fun DefaultKeyboard(
     allowVibration: Boolean,
     fractional: String,
     middleZero: Boolean,
+    acButton: Boolean,
+    addBracket: () -> Unit,
 ) {
     ColumnWithConstraints(modifier) {
         val fractionalIcon = remember { if (fractional == Token.Digit.dot) UnittoIcons.Dot else UnittoIcons.Comma }
@@ -85,8 +90,13 @@ internal fun DefaultKeyboard(
         // Column modifier
         val cModifier = Modifier.weight(1f)
         Row(cModifier) {
-            KeyboardButtonFilled(bModifier, UnittoIcons.LeftBracket, allowVibration) { addDigit(Token.Operator.leftBracket) }
-            KeyboardButtonFilled(bModifier, UnittoIcons.RightBracket, allowVibration) { addDigit(Token.Operator.rightBracket) }
+            if (acButton) {
+                KeyboardButtonTertiary(bModifier, UnittoIcons.Clear, allowVibration) { clearInput() }
+                KeyboardButtonFilled(bModifier, UnittoIcons.Brackets, allowVibration) { addBracket() }
+            } else {
+                KeyboardButtonFilled(bModifier, UnittoIcons.LeftBracket, allowVibration) { addDigit(Token.Operator.leftBracket) }
+                KeyboardButtonFilled(bModifier, UnittoIcons.RightBracket, allowVibration) { addDigit(Token.Operator.rightBracket) }
+            }
             KeyboardButtonFilled(bModifier, UnittoIcons.Power, allowVibration) { addDigit(Token.Operator.power) }
             KeyboardButtonFilled(bModifier, UnittoIcons.Root, allowVibration) { addDigit(Token.Operator.sqrt) }
         }
@@ -188,7 +198,9 @@ private fun PreviewConverterKeyboard() {
         deleteDigit = {},
         allowVibration = false,
         fractional = FormatterSymbols.Spaces.fractional,
-        middleZero = false
+        middleZero = false,
+        acButton = true,
+        addBracket = {}
     )
 }
 
diff --git a/feature/settings/src/main/java/com/sadellie/unitto/feature/settings/calculator/CalculatorSettingsScreen.kt b/feature/settings/src/main/java/com/sadellie/unitto/feature/settings/calculator/CalculatorSettingsScreen.kt
index 5fcaf898..1674c6c7 100644
--- a/feature/settings/src/main/java/com/sadellie/unitto/feature/settings/calculator/CalculatorSettingsScreen.kt
+++ b/feature/settings/src/main/java/com/sadellie/unitto/feature/settings/calculator/CalculatorSettingsScreen.kt
@@ -88,7 +88,8 @@ private fun PreviewCalculatorSettingsScreen() {
             middleZero = false,
             partialHistoryView = true,
             precision = 3,
-            outputFormat = OutputFormat.PLAIN
+            outputFormat = OutputFormat.PLAIN,
+            acButton = true,
         ),
         navigateUpAction = {},
         updatePartialHistoryView = {}
diff --git a/feature/settings/src/main/java/com/sadellie/unitto/feature/settings/converter/ConverterSettingsScreen.kt b/feature/settings/src/main/java/com/sadellie/unitto/feature/settings/converter/ConverterSettingsScreen.kt
index 61b5b4bb..0fa6c17c 100644
--- a/feature/settings/src/main/java/com/sadellie/unitto/feature/settings/converter/ConverterSettingsScreen.kt
+++ b/feature/settings/src/main/java/com/sadellie/unitto/feature/settings/converter/ConverterSettingsScreen.kt
@@ -147,6 +147,7 @@ private fun PreviewConverterSettingsScreen() {
             enableToolsExperiment = false,
             latestLeftSideUnit = "kilometer",
             latestRightSideUnit = "mile",
+            acButton = true,
         ),
         navigateUpAction = {},
         navigateToUnitsGroup = {},
diff --git a/feature/settings/src/main/java/com/sadellie/unitto/feature/settings/display/DisplayScreen.kt b/feature/settings/src/main/java/com/sadellie/unitto/feature/settings/display/DisplayScreen.kt
index b6da7f26..77209105 100644
--- a/feature/settings/src/main/java/com/sadellie/unitto/feature/settings/display/DisplayScreen.kt
+++ b/feature/settings/src/main/java/com/sadellie/unitto/feature/settings/display/DisplayScreen.kt
@@ -62,6 +62,8 @@ import com.sadellie.unitto.core.ui.common.SegmentedButtonsRow
 import com.sadellie.unitto.core.ui.common.UnittoEmptyScreen
 import com.sadellie.unitto.core.ui.common.UnittoListItem
 import com.sadellie.unitto.core.ui.common.UnittoScreenWithLargeTopBar
+import com.sadellie.unitto.core.ui.common.key.UnittoIcons
+import com.sadellie.unitto.core.ui.common.key.unittoicons.Clear
 import com.sadellie.unitto.feature.settings.components.ColorSelector
 import com.sadellie.unitto.feature.settings.components.MonetModeSelector
 import io.github.sadellie.themmo.MonetMode
@@ -113,6 +115,8 @@ internal fun DisplayRoute(
                 },
                 systemFont = prefs.systemFont,
                 updateSystemFont = viewModel::updateSystemFont,
+                acButton = prefs.acButton,
+                updateAcButton = viewModel::updateAcButton,
                 middleZero = prefs.middleZero,
                 updateMiddleZero = viewModel::updateMiddleZero,
                 navigateToLanguages = navigateToLanguages
@@ -136,6 +140,8 @@ private fun DisplayScreen(
     onMonetModeChange: (MonetMode) -> Unit,
     systemFont: Boolean,
     updateSystemFont: (Boolean) -> Unit,
+    acButton: Boolean,
+    updateAcButton: (Boolean) -> Unit,
     middleZero: Boolean,
     updateMiddleZero: (Boolean) -> Unit,
     navigateToLanguages: () -> Unit,
@@ -266,6 +272,15 @@ private fun DisplayScreen(
                 onSwitchChange = updateSystemFont
             )
 
+            UnittoListItem(
+                icon = UnittoIcons.Clear,
+                iconDescription = stringResource(R.string.settings_middle_zero),
+                headlineText = stringResource(R.string.settings_ac_button),
+                supportingText = stringResource(R.string.settings_ac_button_support),
+                switchState = acButton,
+                onSwitchChange = updateAcButton
+            )
+
             UnittoListItem(
                 icon = Icons.Default.ExposureZero,
                 iconDescription = stringResource(R.string.settings_middle_zero),
@@ -304,6 +319,8 @@ private fun Preview() {
             onMonetModeChange = themmoController::setMonetMode,
             systemFont = false,
             updateSystemFont = {},
+            acButton = false,
+            updateAcButton = {},
             middleZero = false,
             updateMiddleZero = {},
             navigateToLanguages = {}
diff --git a/feature/settings/src/main/java/com/sadellie/unitto/feature/settings/display/DisplayViewModel.kt b/feature/settings/src/main/java/com/sadellie/unitto/feature/settings/display/DisplayViewModel.kt
index 21e9a5d7..7a4ce77c 100644
--- a/feature/settings/src/main/java/com/sadellie/unitto/feature/settings/display/DisplayViewModel.kt
+++ b/feature/settings/src/main/java/com/sadellie/unitto/feature/settings/display/DisplayViewModel.kt
@@ -37,60 +37,48 @@ class DisplayViewModel @Inject constructor(
     val prefs = userPrefsRepository.displayPrefs
         .stateIn(viewModelScope, null)
 
-    /**
-     * @see UserPreferencesRepository.updateThemingMode
-     */
     fun updateThemingMode(themingMode: ThemingMode) {
         viewModelScope.launch {
             userPrefsRepository.updateThemingMode(themingMode)
         }
     }
 
-    /**
-     * @see UserPreferencesRepository.updateDynamicTheme
-     */
     fun updateDynamicTheme(enabled: Boolean) {
         viewModelScope.launch {
             userPrefsRepository.updateDynamicTheme(enabled)
         }
     }
 
-    /**
-     * @see UserPreferencesRepository.updateAmoledTheme
-     */
     fun updateAmoledTheme(enabled: Boolean) {
         viewModelScope.launch {
             userPrefsRepository.updateAmoledTheme(enabled)
         }
     }
 
-    /**
-     * @see UserPreferencesRepository.updateCustomColor
-     */
     fun updateCustomColor(color: Color) {
         viewModelScope.launch {
             userPrefsRepository.updateCustomColor(color)
         }
     }
 
-    /**
-     * @see UserPreferencesRepository.updateMonetMode
-     */
     fun updateMonetMode(monetMode: MonetMode) {
         viewModelScope.launch {
             userPrefsRepository.updateMonetMode(monetMode)
         }
     }
 
-    /**
-     * @see UserPreferencesRepository.updateSystemFont
-     */
     fun updateSystemFont(enabled: Boolean) {
         viewModelScope.launch {
             userPrefsRepository.updateSystemFont(enabled)
         }
     }
 
+    fun updateAcButton(enabled: Boolean) {
+        viewModelScope.launch {
+            userPrefsRepository.updateAcButton(enabled)
+        }
+    }
+
     fun updateMiddleZero(enabled: Boolean) = viewModelScope.launch {
         userPrefsRepository.updateMiddleZero(enabled)
     }