Commingle Money

A Flutter package for working with monetary values, open sourced from the Commingle app. It includes global currency definitions, widgets for displaying amounts, input controllers for smooth, user-friendly editing and other monetary utilities.

Explore the Example App

Clone the repository and run the included Example app to see the library in action. The interactive demos let you explore features, validate their usefulness, and inspect the underlying implementation.

🏷️ Money Label

MoneyLabel is a rich and flexible widget for presenting Money values.

  • Odometer-style animations for amount changes
  • Configurable decimal behavior - e.g. round, show when needed…
  • Currency and negative sign display choice
  • Custom colors for positive, negative, and zero values
  • Full control over text styles
MoneyLabel(
  money: Money(
    currencyCode: 'USD', 
    amount: Decimal.parse('1234.56')
  ),
  fractionalMode: MoneyLabelFractionalMode.flexible,
  displayCurrency: true,
  displayNegativeSign: true,
  separators: AmountFormatSeparatorsData(
    grouping: 
    decimal: 
  ),
  animation: MoneyLabelAnimation(
    duration: 
    curve: 
  ),
  primaryTextStyle: Theme.of(context).textTheme.bodyLarge,
  secondaryTextStyle: Theme.of(context).textTheme.bodySmall,
  positiveColor: Colors.green,
  negativeColor: Colors.red,
  zeroColor: Colors.grey
  primaryTextStyle: TextStyle(fontSize: 24, fontWeight: FontWeight.bold),
)

You can wrap your app with the MoneyLabelDefaults inherited widget to provide default styles, colors, and behavior for all MoneyLabel instances.

💳 Money Editing Controller

MoneyEditingController is a powerful controller you can assign to any TextField to handle monetary input with precision, formatting, and validation. It supports:

  • Simple input
  • Formula input - user can type 2 + 3(4 - 2) ÷ 5 × 1.5
  • Automatic rounding and formatting when unfocused
final controller = MoneyEditingController(
  currencyCode: CurrencyCodes.usd, // or 'USD'
  amount: Decimal.parse('123.45'),
  separators: AmountFormatSeparatorsData(
    grouping: 
    decimal: 
  ),
);

TextField(
  controller: controller.textController,
  focusNode: controller.focusNode,
  keyboardType: const TextInputType.numberWithOptions(decimal: true),
)

You can listen to changes as the user types:

controller.addListener(() {
  final amount = controller.value;
  // your code
});

You can also set the value programmatically using value setter or to just change a currency using currencyCode setter.

You can listen as the user types, e.g., to highlight the field in red or disable the save button based on the overall state:

controller.addListener(() {
  final state = controller.state;
  // handle: AmountEditingState.value, .empty, .zero, or .error
});

🔢 Amount Editing Controller

AmountEditingController is a lightweight alternative to MoneyEditingController that operates directly on Decimal values. It lets you control the desired precision without involving currency logic.

💡 MoneyEditingController is built on top of AmountEditingController.

💵 Money

Money is a simple yet powerful value class that combines a currencyCode with a Decimal amount.

Money(
  currencyCode: CurrencyCodes.usd, // or simply 'USD'
  amount: Decimal.parse('123.45'),
);

It provides utility methods like:

  • rounded(): 2.99 → 3
  • roundedToCurrencyPrecision(): 2.567 → 2.57.
  • abs()

You can also use math operators directly: + – × ÷. All operations return a new Money instance, rounded to the currency precision. You can combine Money values of the same currency with int, double, or Decimal values.

final usd1 = Money(currencyCode: 'USD', amount: Decimal.fromInt(1))
final usd2 = Money(currencyCode: 'USD', amount: Decimal.fromInt(2))

final total = usd1 + usd2 * 3 - 1 / 2; // = 6.5 USD

🌍 Currency

The library includes a comprehensive list of 155 worldwide currencies, each with detailed metadata.

final usd = Currency.fromCode('USD');

// Result:
Currency(
  code: 'USD',
  precision: 2,
  emojiFlag: '🇺🇸',
  symbol: '$',
  englishName: 'United States Dollar',
  englishCountryNames: {
    'United States',
    'Ecuador',
    'El Salvador',
    'Panama',
    …
  },
),

You can retrieve all currencies using: Currency.list(), or filter them as user types:

Currency.list((c) => c.englishName.contains(searchQuery))

You can also use constants like CurrencyCodes.chf for quick access to a curated subset of popular currencies.

🧮 Decimal Utilities

DecimalUtils is an extension on Decimal that provides helpful utilities for rounding, scaling, and working with numeric data in a finance-friendly way.

  • round2() rounds the decimal to two decimal places (unless scale is provided).
  • upperBound and lowerBound help round values to chart-friendly boundaries,
    e.g. 1234.56 → 1300 (upper), 1200 (lower).
  • utility functions like min, max, and sum
  • converters Decimal → int as well as double → Decimal

🙌 Acknowledgements

This library wouldn’t be possible without the excellent work of the Flutter community.

decimal, equatable, expressions, animated_flip_counter

While not part of the core library, I recommend using locale_plus like demonstrated in Example app.

🤝 Contributing

Contributions are very welcome! If you spot a bug, want to improve something, or add a feature, feel free to fork the repository and raise a pull request.

🎯 Trivia

📄 Copyright and License

Commingle Money is maintained by Chris Rutkowski as part of the Commingle app, and open-sourced under the MIT License.

Libraries

commingle_money