diff --git a/app/src/main/java/net/helcel/cowspent/android/bill_edit/EditBillActivity.kt b/app/src/main/java/net/helcel/cowspent/android/bill_edit/EditBillActivity.kt
index 9a3027b..9127582 100644
--- a/app/src/main/java/net/helcel/cowspent/android/bill_edit/EditBillActivity.kt
+++ b/app/src/main/java/net/helcel/cowspent/android/bill_edit/EditBillActivity.kt
@@ -329,20 +329,18 @@ class EditBillActivity : AppCompatActivity() {
         if (splitMode != SplitMode.EVEN) {
             val splits: Map<Long, Double> = if (splitMode == SplitMode.CUSTOM) {
                 viewModel.owersCustomSplit.filter { (id, amountStr) ->
-                    viewModel.owersSelection[id] == true && (amountStr.replace(',', '.').toDoubleOrNull()
-                        ?: 0.0) > 0
+                    viewModel.owersSelection[id] == true && viewModel.parseAmountFromUi(amountStr) > 0
                 }.mapValues {
-                    val uiAmount = it.value.replace(',', '.').toDoubleOrNull() ?: 0.0
+                    val uiAmount = viewModel.parseAmountFromUi(it.value)
                     SupportUtil.round2(uiAmount / viewModel.selectedCurrencyRate)
                 }
             } else { // PERCENT
                 val totalAmount = viewModel.amountAsDouble
                 viewModel.owersPercentSplit.filter { (id, percentStr) ->
-                    viewModel.owersSelection[id] == true && (percentStr.replace(',', '.').toDoubleOrNull()
-                        ?: 0.0) > 0
+                    viewModel.owersSelection[id] == true && viewModel.parseAmountFromUi(percentStr) > 0
                 }.mapValues {
-                    val percent = it.value.replace(',', '.').toDoubleOrNull() ?: 0.0
-                    val uiAmount = totalAmount * percent / 100.0
+                    val percent = viewModel.parseAmountFromUi(it.value)
+                    val uiAmount = SupportUtil.round2(totalAmount * percent / 100.0)
                     SupportUtil.round2(uiAmount / viewModel.selectedCurrencyRate)
                 }
             }
diff --git a/app/src/main/java/net/helcel/cowspent/android/bill_edit/EditBillScreen.kt b/app/src/main/java/net/helcel/cowspent/android/bill_edit/EditBillScreen.kt
index eb255f6..385c0e6 100644
--- a/app/src/main/java/net/helcel/cowspent/android/bill_edit/EditBillScreen.kt
+++ b/app/src/main/java/net/helcel/cowspent/android/bill_edit/EditBillScreen.kt
@@ -193,8 +193,9 @@ fun BillBasicInfoSection(
 
     OutlinedTextField(
         value = viewModel.amount,
-        onValueChange = {
-            viewModel.amount = it
+        onValueChange = { nv->
+            val filteredValue = nv.filter { it in "0123456789.+-*/" }
+            viewModel.amount = filteredValue
             viewModel.updateSplits()
         },
         enabled = canEdit,
@@ -233,7 +234,7 @@ fun BillBasicInfoSection(
                 Icon(Icons.Default.SwapHoriz, contentDescription = "Change Currency")
             }
         },
-        keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Number)
+        keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Text)
     )
 
     Spacer(modifier = Modifier.height(8.dp))
@@ -442,13 +443,14 @@ fun OwerSelectionSection(
                 
                 BasicTextField(
                     value = value,
-                    onValueChange = {
+                    onValueChange = { nv ->
+                        val filteredValue = nv.filter { it in "0123456789.+-*/" }
                         if (viewModel.splitMode == SplitMode.PERCENT) {
-                            viewModel.owersPercentSplit[member.id] = it
+                            viewModel.owersPercentSplit[member.id] = filteredValue
                         } else {
-                            viewModel.owersCustomSplit[member.id] = it
+                            viewModel.owersCustomSplit[member.id] = filteredValue
                         }
-                        viewModel.owersSelection[member.id] = (it != "")
+                        viewModel.owersSelection[member.id] = (filteredValue != "")
                     },
                     modifier = Modifier
                         .width(80.dp)
diff --git a/app/src/main/java/net/helcel/cowspent/android/bill_edit/EditBillViewModel.kt b/app/src/main/java/net/helcel/cowspent/android/bill_edit/EditBillViewModel.kt
index 95844fa..6d8ba58 100644
--- a/app/src/main/java/net/helcel/cowspent/android/bill_edit/EditBillViewModel.kt
+++ b/app/src/main/java/net/helcel/cowspent/android/bill_edit/EditBillViewModel.kt
@@ -44,18 +44,26 @@ class EditBillViewModel : ViewModel() {
 
     var dialogState by mutableStateOf<DialogState?>(null)
 
-    val amountAsDouble: Double
-        get() {
-            return parseAmount(amount) ?: try {
-                evalMath(amount.replace(',', '.'))
-            } catch (_: Exception) {
-                0.0
-            }
+    fun parseAmountFromUi(input: String): Double {
+        if (input.isBlank()) return 0.0
+        val sanitized = input.replace(',', '.')
+        // If it contains any math operator, try evalMath first
+        if (sanitized.any { it in "+-*/" }) {
+            try {
+                val result = evalMath(sanitized)
+                if (result != 0.0) return SupportUtil.round2(result)
+            } catch (_: Exception) {}
         }
+        val parsed = parseAmount(input) ?: 0.0
+        return SupportUtil.round2(parsed)
+    }
+
+    val amountAsDouble: Double
+        get() = parseAmountFromUi(amount)
 
     fun getEvenSplit(): Double {
         val selectedOwersCount = owersSelection.count { it.value }
-        return if (selectedOwersCount > 0) amountAsDouble / selectedOwersCount else 0.0
+        return if (selectedOwersCount > 0) SupportUtil.round2(amountAsDouble / selectedOwersCount) else 0.0
     }
 
     fun updateSplits() {
@@ -109,13 +117,13 @@ class EditBillViewModel : ViewModel() {
         return if (splitMode == SplitMode.PERCENT) {
             val customTotal = owersPercentSplit.entries
                 .filter { owersSelection[it.key] == true }
-                .sumOf { it.value.replace(',', '.').toDoubleOrNull() ?: 0.0 }
-            100.0 - customTotal
+                .sumOf { parseAmountFromUi(it.value) }
+            SupportUtil.round2(100.0 - customTotal)
         } else {
             val customTotal = owersCustomSplit.entries
                 .filter { owersSelection[it.key] == true }
-                .sumOf { it.value.replace(',', '.').toDoubleOrNull() ?: 0.0 }
-            amountAsDouble - customTotal
+                .sumOf { parseAmountFromUi(it.value) }
+            SupportUtil.round2(amountAsDouble - customTotal)
         }
     }