font-synthesis-weight

Baseline 2023

Newly available

Since March 2023, this feature works across the latest devices and browser versions. This feature might not work in older devices or browsers.

The font-synthesis-weight CSS property lets you specify whether or not the browser may synthesize the bold typeface when it is missing in a font family.

It is often convenient to use the shorthand property font-synthesis to control all typeface synthesis values.

Syntax

/* Keyword values */
font-synthesis-weight: auto;
font-synthesis-weight: none;

/* Global values */
font-synthesis-weight: inherit;
font-synthesis-weight: initial;
font-synthesis-weight: revert;
font-synthesis-weight: revert-layer;
font-synthesis-weight: unset;

Values

auto: Indicates that the missing bold typeface may be synthesized by the browser if needed.
none: Indicates that the synthesis of the missing bold typeface by the browser is not allowed.

Formal definition

Initial value	`auto`
Applies to	all elements and text. It also applies to `::first-letter` and `::first-line`.
Inherited	yes
Computed value	as specified
Animation type	discrete

Formal syntax

font-synthesis-weight = 
  auto  |
  none

Examples

Disabling synthesis of bold typeface

This example shows turning off synthesis of the bold typeface by the browser in the Montserrat font.

HTML

<p class="english">
  This is the default <strong>bold typeface</strong> and
  <em>oblique typeface</em>.
</p>

<p class="english no-syn">
  The <strong>bold typeface</strong> is turned off here but not the
  <em>oblique typeface</em>.
</p>

CSS

@import url("https://fonts.googleapis.com/css2?family=Montserrat&display=swap");

.english {
  font-family: "Montserrat", sans-serif;
}
.no-syn {
  font-synthesis-weight: none;
}

Result

Specifications

Specification
CSS Fonts Module Level 4 # font-synthesis-weight

Browser compatibility

	Desktop					Mobile
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet	WebView Android
`font-synthesis-weight`	97	97	111	83	16.4	97	111	68	16.4	18.0	97
`auto`	97	97	111	83	16.4	97	111	68	16.4	18.0	97
`none`	97	97	111	83	16.4	97	111	68	16.4	18.0	97