Use a custom font

Although Android and iOS offer high quality system fonts, one of the most common requests from designers is for custom fonts. For example, you might have a custom-built font from a designer, or perhaps you downloaded a font from Google Fonts.

Flutter works with custom fonts and you can apply a custom font across an entire app or to individual widgets. This recipe creates an app that uses custom fonts with the following steps:

1. Import the font files.
2. Declare the font in the pubspec.
3. Set a font as the default.
4. Use a font in a specific widget.

1. Import the font files

To work with a font, import the font files into the project. It’s common practice to put font files in a fonts or assets folder at the root of a Flutter project.

For example, to import the Raleway and Roboto Mono font files into a project, the folder structure might look like this:

awesome_app/
  fonts/
    Raleway-Regular.ttf
    Raleway-Italic.ttf
    RobotoMono-Regular.ttf
    RobotoMono-Bold.ttf

Supported font formats

Flutter supports the following font formats:

• .ttf
• .otf

Flutter does not support .woff and .woff2 fonts for all platforms.

2. Declare the font in the pubspec

Once you’ve identified a font, tell Flutter where to find it. You can do this by including a font definition in the pubspec.yaml file.

flutter:
  fonts:
    - family: Raleway
      fonts:
        - asset: fonts/Raleway-Regular.ttf
        - asset: fonts/Raleway-Italic.ttf
          style: italic
    - family: RobotoMono
      fonts:
        - asset: fonts/RobotoMono-Regular.ttf
        - asset: fonts/RobotoMono-Bold.ttf
          weight: 700

pubspec.yaml option definitions

The family determines the name of the font, which you use in the fontFamily property of a TextStyle object.

The asset is a path to the font file, relative to the pubspec.yaml file. These files contain the outlines for the glyphs in the font. When building the app, these files are included in the app’s asset bundle.

A single font can reference many different files with different outline weights and styles:

• The weight property specifies the weight of the outlines in the file as an integer multiple of 100, between 100 and 900. These values correspond to the FontWeight and can be used in the fontWeight property of a TextStyle object. For example, if you want to use the RobotoMono-Bold font defined above, you would set fontWeight to FontWeight.w700 in your TextStyle.

  Note that defining the weight property does not override the actual weight of the font. You would not be able to access RobotoMono-Bold with FontWeight.w100, even if its weight was set to 100.

• The style property specifies whether the outlines in the file are italic or normal. These values correspond to the FontStyle and can be used in the fontStyle property of a TextStyle object. For example, if you want to use the Raleway-Italic font defined above, you would set fontStyle to FontStyle.italic in your TextStyle.

  Note that defining the style property does not override the actual style of the font; You would not be able to access Raleway-Italic with FontStyle.normal, even if its style was set to normal.

3. Set a font as the default

You have two options for how to apply fonts to text: as the default font or only within specific widgets.

To use a font as the default, set the fontFamily property as part of the app’s theme. The value provided to fontFamily must match the family name declared in the pubspec.yaml.

MaterialApp(
  title: 'Custom Fonts',
  // Set Raleway as the default app font.
  theme: ThemeData(fontFamily: 'Raleway'),
  home: const MyHomePage(),
);

For more information on themes, see the Using Themes to share colors and font styles recipe.

4. Use the font in a specific widget

If you want to apply the font to a specific widget, such as a Text widget, provide a TextStyle to the widget.

In this example, apply the RobotoMono font to a single Text widget. Once again, the fontFamily must match the family name declared in the pubspec.yaml.

Text(
  'Roboto Mono sample',
  style: TextStyle(fontFamily: 'RobotoMono'),
);

TextStyle

If a TextStyle object specifies a weight or style for which there is no exact font file, the engine uses one of the more generic files for the font and attempts to extrapolate outlines for the requested weight and style.

Complete example

Fonts

The Raleway and RobotoMono fonts were downloaded from Google Fonts.

pubspec.yaml

name: custom_fonts
description: An example of how to use custom fonts with Flutter

dependencies:
  flutter:
    sdk: flutter

dev_dependencies:
  flutter_test:
    sdk: flutter

flutter:
  fonts:
    - family: Raleway
      fonts:
        - asset: fonts/Raleway-Regular.ttf
        - asset: fonts/Raleway-Italic.ttf
          style: italic
    - family: RobotoMono
      fonts:
        - asset: fonts/RobotoMono-Regular.ttf
        - asset: fonts/RobotoMono-Bold.ttf
          weight: 700
  uses-material-design: true

main.dart

import 'package:flutter/material.dart';

void main() => runApp(const MyApp());

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Custom Fonts',
      // Set Raleway as the default app font.
      theme: ThemeData(fontFamily: 'Raleway'),
      home: const MyHomePage(),
    );
  }
}

class MyHomePage extends StatelessWidget {
  const MyHomePage({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      // The AppBar uses the app-default Raleway font.
      appBar: AppBar(title: const Text('Custom Fonts')),
      body: const Center(
        // This Text widget uses the RobotoMono font.
        child: Text(
          'Roboto Mono sample',
          style: TextStyle(fontFamily: 'RobotoMono'),
        ),
      ),
    );
  }
}