pub version pub points pub likes MIT license Dart SDK

MXFormatter

A lightweight, zero-dependency pure-Dart package for formatting quantities, percentages, and monetary values.

  • Rounds to a configurable number of decimal places.
  • Strips trailing zeros (and the decimal point when unnecessary).
  • Adds a configurable thousand separator (default: space ' ').
  • Works on all platforms — Android, iOS, Linux, macOS, Web, Windows.

Features

Input Output Formatter
10.12123123 "10.12" QuantityFormatter.format
10.0 "10" QuantityFormatter.format
10.10 "10.1" QuantityFormatter.format
10.12123123 "10.12%" QuantityFormatter.formatPercent
10.0 "10%" QuantityFormatter.formatPercent
102_321_121 "102 321 121" MoneyFormatter.format
10_321_121.21 "10 321 121.21" MoneyFormatter.format
-1_500.5 "-1 500.5" MoneyFormatter.format

Getting started

Add the package to your pubspec.yaml:

dependencies:
  mx_formatter: ^1.0.0

Then run:

dart pub get

Usage

Import the library:

import 'package:mx_formatter/mx_formatter.dart';

The package offers two equivalent styles — pick the one you prefer:

Style Example
Extension (fluent) 102321121.moneyFormat()
Static class (explicit) MoneyFormatter.format(102321121)

Extension API (fluent style)

Every num value (int and double) gains three extension methods:

// Money
102321121.moneyFormat();          // "102 321 121"
10321121.21.moneyFormat();        // "10 321 121.21"
1000000.moneyFormat(thousandSeparator: ','); // "1,000,000"

// Quantity
10.12123123.qtyFormat();          // "10.12"
10.0.qtyFormat();                 // "10"
42.qtyFormat();                   // "42"  (int works too)

// Percentage
10.12123123.percentFormat();      // "10.12%"
10.0.percentFormat();             // "10%"
50.percentFormat();               // "50%"  (int works too)

Static API

Quantity formatting

// Rounds to 2 decimal places by default and strips trailing zeros.
QuantityFormatter.format(10.12123123);              // "10.12"
QuantityFormatter.format(10.0);                     // "10"
QuantityFormatter.format(10.10);                    // "10.1"
QuantityFormatter.format(0.0);                      // "0"
QuantityFormatter.format(-3.5);                     // "-3.5"

// Custom number of decimal places.
QuantityFormatter.format(10.123456, maxDecimalPlaces: 4); // "10.1235"
QuantityFormatter.format(10.123456, maxDecimalPlaces: 0); // "10"

Percentage formatting

// Same as format(), but appends the '%' symbol.
QuantityFormatter.formatPercent(10.12123123); // "10.12%"
QuantityFormatter.formatPercent(10.0);        // "10%"
QuantityFormatter.formatPercent(0.0);         // "0%"
QuantityFormatter.formatPercent(-5.5);        // "-5.5%"

Money formatting

// Space is the default thousand separator.
MoneyFormatter.format(102321121);    // "102 321 121"
MoneyFormatter.format(10321121.21);  // "10 321 121.21"
MoneyFormatter.format(1000);         // "1 000"
MoneyFormatter.format(1000000);      // "1 000 000"
MoneyFormatter.format(999);          // "999"
MoneyFormatter.format(0);            // "0"
MoneyFormatter.format(1500.5);       // "1 500.5"
MoneyFormatter.format(-1500.5);      // "-1 500.5"

// Custom separators.
MoneyFormatter.format(1000000, thousandSeparator: ','); // "1,000,000"
MoneyFormatter.format(1500.5,  decimalSeparator:  ','); // "1 500,5"

// European style: dot thousands, comma decimal.
MoneyFormatter.format(
  1234567.89,
  thousandSeparator: '.',
  decimalSeparator:  ',',
); // "1.234.567,89"

API reference

NumMXFormatterExtension (on num)

Extension on num — automatically available on every int and double.

Method Signature Description
moneyFormat ({int maxDecimalPlaces, String thousandSeparator, String decimalSeparator}) Formats as monetary string
qtyFormat ({int maxDecimalPlaces}) Formats as quantity string
percentFormat ({int maxDecimalPlaces}) Formats as percentage string

All parameters are optional (same defaults as the static classes).

QuantityFormatter

A utility class with only static methods (cannot be instantiated).

format

static String format(
  double value, {
  int maxDecimalPlaces = 2,
})

Rounds value to at most maxDecimalPlaces decimal digits and removes trailing zeros. The decimal point itself is also removed when the fractional part becomes zero.

Parameter Type Default Description
value double — The number to format
maxDecimalPlaces int 2 Max digits after the decimal point (must be ≥ 0)

formatPercent

static String formatPercent(
  double value, {
  int maxDecimalPlaces = 2,
})

Equivalent to format() with a % character appended to the result.

MoneyFormatter

A utility class with only static methods (cannot be instantiated).

format

static String format(
  double value, {
  int maxDecimalPlaces = 2,
  String thousandSeparator = ' ',
  String decimalSeparator = '.',
})

Formats value as a monetary string. Integer digits are grouped by thousandSeparator every three digits from the right. The fractional part is rounded to maxDecimalPlaces digits with trailing zeros stripped.

Parameter Type Default Description
value double — The number to format
maxDecimalPlaces int 2 Max digits after the decimal point (must be ≥ 0)
thousandSeparator String ' ' Inserted between each group of 3 integer digits
decimalSeparator String '.' Separates the integer and fractional parts

Additional information

Contributions are welcome! Please open an issue or submit a pull request.

Libraries

mx_formatter
A Dart package for formatting quantities, percentages, and monetary values.