font-synthesis-style

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since ⁨March 2023⁩.

The font-synthesis-style CSS property lets you specify whether or not the browser may synthesize the oblique 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

css

/* Keyword values */
font-synthesis-style: auto;
font-synthesis-style: none;
font-synthesis-style: oblique-only;

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

Values

auto: Indicates that the missing oblique typeface may be synthesized by the browser if needed.
none: Indicates that the synthesis of the missing oblique typeface by the browser is not allowed.
oblique-only: Same as auto, but no font synthesis occurs if font-style: italic is set.

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-style = 
  auto          |
  none          |
  oblique-only

Examples

Disabling synthesis of oblique typeface

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

HTML

html

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

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

CSS

css

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

.english {
  font-family: "Montserrat", sans-serif;
}

.no-syn {
  font-synthesis-style: none;
}

Result

Comparison of font-synthesis-style values

This example compares all the font-synthesis-style values using italic and oblique styled texts.

HTML

html

<div class="fss-none">
  <h2>font-synthesis-style: none</h2>
  <p class="oblique">This text is set to <code>oblique</code></p>
  <p class="italic">This text is set to <code>italic</code></p>
</div>

<div class="fss-auto">
  <h2>font-synthesis-style: auto</h2>
  <p class="oblique">This text is set to <code>oblique</code></p>
  <p class="italic">This text is set to <code>italic</code></p>
</div>

<div class="fss-oblique-only">
  <h2>font-synthesis-style: oblique-only</h2>
  <p class="oblique">This text is set to <code>oblique</code></p>
  <p class="italic">This text is set to <code>italic</code></p>
</div>

CSS

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

p {
  font-family: "Montserrat", sans-serif;
  font-size: 1.2rem;
}

@supports not (font-synthesis-style: oblique-only) {
  body::before {
    content: "Your browser doesn't support the 'oblique-only' value.";
    background-color: #ffcd33;
    display: block;
    width: 100%;
    text-align: center;
  }
}

css

/* Specify style of the font synthesis */
.fss-none {
  font-synthesis-style: none;
}

.fss-auto {
  font-synthesis-style: auto;
}

.fss-oblique-only {
  font-synthesis-style: oblique-only;
}

/* Set font styles */
.oblique {
  font-style: oblique;
}

.italic {
  font-style: italic;
}

/* Styles for the demonstration */
.oblique::after {
  content: " (font-style: oblique)";
  font-size: 0.8rem;
  vertical-align: sub;
}

.italic::after {
  content: " (font-style: italic)";
  font-size: 0.8rem;
  vertical-align: sub;
}

Result

Specifications

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

Browser compatibility

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This page was last modified on ⁨Aug 5, 2025⁩ by MDN contributors.

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