Manage regional formats

Text fields and related components, such as date and time pickers, automatically apply locale-specific formatting patterns. These include the formatting of numbers, dates, times, and currencies. The patterns are determined by the system's locale or a custom locale set within your application, ensuring consistent data display across platforms.

Locale formatting patterns

Formatting in Compose Multiplatform respects platform-specific locale conventions for:

Numeric separators. Thousands can get separated by a comma or a period: 1,234.56 in en-US and 1.234,56 in de-DE.
Date/Time patterns. The date of December 1 looks like 12/1/20 in en-US, while the same date in fr-CA looks like 2020-12-01.
Currency symbols and placement. The local currency symbol can be placed either before or after the digits: $5,001 in en-US and 5.001,00 € in fr-FR.

These regional formats work out of the box for both system locales and custom locale overrides defined in your app.

Formatting is currently implemented using the kotlinx-datetime library on iOS and the JDK API on Android and desktop. Here is an example of managing localized date and currency values in the iOS source set:

import androidx.compose.foundation.layout.Column
import androidx.compose.material.Text
import androidx.compose.runtime.Composable
import kotlinx.datetime.Clock
import kotlinx.datetime.TimeZone
import kotlinx.datetime.todayIn
import platform.Foundation.NSNumber
import platform.Foundation.NSNumberFormatter
import platform.Foundation.NSNumberFormatterCurrencyStyle
import platform.Foundation.NSLocale
import platform.Foundation.currentLocale

@Composable
fun RegionalFormatExample() {
    val currentLocale = NSLocale.current
    val languageCode = currentLocale.languageCode 
    val countryCode = currentLocale.countryCode 

    // Sample value to format as currency
    val amount = 1234.56

    // Uses NSNumberFormatter for currency formatting on iOS
    val currencyFormatter = NSNumberFormatter().apply { 
        numberStyle = NSNumberFormatterCurrencyStyle
        locale = currentLocale
    }
    val formattedCurrency = currencyFormatter.stringFromNumber(NSNumber(amount)) 

    // Gets current date using `kotlinx-datetime`
    val today = Clock.System.todayIn(TimeZone.currentSystemDefault())
    val formattedDate = today.toString()

    Column {
        Text("Current language: $languageCode")
        Text("Current country: $countryCode")
        Text("Amount: $amount")
        Text("Formatted currency: $formattedCurrency")
        Text("Today's date: $formattedDate")
    }
}

Ensure consistent formatting

Although there is no common API for a unified multiplatform solution, the formatting behavior is still consistent in most cases. To ensure the formatting is correct for all supported regions:

Test edge cases such as large numbers, negative values, or zeroes.
Verify formatting for all supported locales on all target platforms.

What's next

Learn how to manage the application's resource environment like in-app theme and language.

Last modified: 28 May 2025