Web/CSS/text-rendering

The text-rendering CSS property provides information to the rendering engine about what to optimize for when rendering text.

The browser makes trade-offs among speed, legibility, and geometric precision.

/* Keyword values */
text-rendering: auto;
text-rendering: optimizeSpeed;
text-rendering: optimizeLegibility;
text-rendering: geometricPrecision;

/* Global values */
text-rendering: inherit;
text-rendering: initial;
text-rendering: unset;

Note: The text-rendering property is an SVG property that is not defined in any CSS standard. However, Gecko and WebKit browsers let you apply this property to HTML and XML content on Windows, macOS, and Linux.

One very visible effect is optimizeLegibility, which enables ligatures (ff, fi, fl, etc.) in text smaller than 20px for some fonts (for example, Microsoft's Calibri, Candara, Constantia, and Corbel, or the DejaVu font family).

Syntax

Values

auto

The browser makes educated guesses about when to optimize for speed, legibility, and geometric precision while drawing text. For differences in how this value is interpreted by the browser, see the compatibility table.

optimizeSpeed

The browser emphasizes rendering speed over legibility and geometric precision when drawing text. It disables kerning and ligatures.

optimizeLegibility

The browser emphasizes legibility over rendering speed and geometric precision. This enables kerning and optional ligatures.

geometricPrecision

The browser emphasizes geometric precision over rendering speed and legibility. Certain aspects of fonts — such as kerning — don't scale linearly. So this value can make text using those fonts look good.

In SVG, when text is scaled up or down, browsers calculate the final size of the text (which is determined by the specified font size and the applied scale) and request a font of that computed size from the platform's font system. But if you request a font size of, say, 9 with a scale of 140%, the resulting font size of 12.6 doesn't explicitly exist in the font system, so the browser rounds the font size to 12 instead. This results in stair-step scaling of text.

But the geometricPrecision property — when fully supported by the rendering engine — lets you scale your text fluidly. For large scale factors, you might see less-than-beautiful text rendering, but the size is what you would expect—neither rounded up nor down to the nearest font size supported by Windows or Linux.

Note: WebKit precisely applies the specified value, but Gecko treats the value the same as optimizeLegibility.

Formal definition

Initial value	auto
Applies to	text elements
Inherited	yes
Computed value	as specified
Animation type	discrete

Formal syntax

auto | optimizeSpeed | optimizeLegibility | geometricPrecision

Examples

Automatic application of optimizeLegibility

This demonstrates how optimizeLegibility is used by browsers automatically when the font-size is smaller than 20px.

HTML

<p class="small">LYoWAT - ff fi fl ffl</p>
<p class="big">LYoWAT - ff fi fl ffl</p>

CSS

.small { font: 19.9px "Constantia", "Times New Roman", "Georgia", "Palatino", serif; }
.big   { font: 20px "Constantia", "Times New Roman", "Georgia", "Palatino", serif; }

optimizeSpeed vs optimizeLegibility

This example shows the difference between the appearance of optimizeSpeed and optimizeLegibility (in your browser; other browsers may vary).

HTML

<p class="speed">LYoWAT - ff fi fl ffl</p>
<p class="legibility">LYoWAT - ff fi fl ffl</p>

CSS

p { font: 1.5em "Constantia", "Times New Roman", "Georgia", "Palatino", serif }

.speed       { text-rendering: optimizeSpeed; }
.legibility  { text-rendering: optimizeLegibility; }

Specifications

Specification	Status	Comment
Scalable Vector Graphics (SVG) 2The definition of 'text-rendering' in that specification.	Candidate Recommendation	No change
Scalable Vector Graphics (SVG) 1.1 (Second Edition)The definition of 'text-rendering' in that specification.	Recommendation	Initial definition

Browser compatibility

The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
text-rendering Non-standard'	Chrome Full support 4 Notes' Full support 4 Notes' Notes' This property is only supported on Windows and Linux. Notes' Initial versions had bugs on Windows and Linux that broke font substitition, small-caps, letter-spacing or caused text to overlap.	Edge Full support 79 Notes' Full support 79 Notes' Notes' This property is only supported on Windows and Linux. Notes' Initial versions had bugs on Windows and Linux that broke font substitition, small-caps, letter-spacing or caused text to overlap.	Firefox Full support 1 Notes' Full support 1 Notes' Notes' This property is only supported on Windows and Linux. Notes' The optimizeSpeed option has no effect on Firefox 4 because the standard code for text rendering is already fast and there is not a faster code path at this time. See bug 595688 for details.	IE No support No	Opera Full support 15	Safari Full support 5	WebView Android Full support 3 Notes' Full support 3 Notes' Notes' From version 3 to 4.3, there is a serious bug where text-rendering: optimizeLegibility causes custom web fonts to not render. This was fixed in version 4.4.	Chrome Android Full support 18 Notes' Full support 18 Notes' Notes' This property is only supported on Windows and Linux. Notes' Initial versions had bugs on Windows and Linux that broke font substitition, small-caps, letter-spacing or caused text to overlap.	Firefox Android Full support 46	Opera Android Full support 14	Safari iOS Full support 4.2	Samsung Internet Android Full support 1.0 Notes' Full support 1.0 Notes' Notes' This property is only supported on Windows and Linux. Samsung Internet is not on Windows or Linux.
auto Non-standard'	Chrome Full support 4 Notes' Full support 4 Notes' Notes' Chrome treats auto as optimizeSpeed.	Edge Full support 79 Notes' Full support 79 Notes' Notes' Edge treats auto as optimizeSpeed.	Firefox Full support 1 Notes' Full support 1 Notes' Notes' If the font size is 20 pixels or higher, Firefox treats auto as optimizeLegibility. For smaller text, Firefox treats auto as optimizeSpeed. The 20-pixel threshold can be changed with the browser.display.auto_quality_min_font_size preference.	IE No support No	Opera Full support 15 Notes' Full support 15 Notes' Notes' Opera treats auto as optimizeSpeed.	Safari Full support 5 Notes' Full support 5 Notes' Notes' Safari treats auto as optimizeSpeed. See WebKit bug 41363.	WebView Android Full support ≤37 Notes' Full support ≤37 Notes' Notes' WebView treats auto as optimizeSpeed.	Chrome Android Full support 18 Notes' Full support 18 Notes' Notes' Chrome treats auto as optimizeSpeed.	Firefox Android Full support 46 Notes' Full support 46 Notes' Notes' If the font size is 20 pixels or higher, Firefox treats auto as optimizeLegibility. For smaller text, Firefox treats auto as optimizeSpeed. The 20-pixel threshold can be changed with the browser.display.auto_quality_min_font_size preference.	Opera Android Full support 14 Notes' Full support 14 Notes' Notes' Opera treats auto as optimizeSpeed.	Safari iOS Full support 4.2 Notes' Full support 4.2 Notes' Notes' Safari treats auto as optimizeSpeed. See WebKit bug 41363.	Samsung Internet Android Full support 1.0 Notes' Full support 1.0 Notes' Notes' Samsung Internet treats auto as optimizeSpeed.
geometricPrecision Non-standard'	Chrome Full support 13 Notes' Full support 13 Notes' Notes' Supports true geometric precision without rounding up or down to the nearest supported font size in the operating system.	Edge Full support 79 Notes' Full support 79 Notes' Notes' Supports true geometric precision without rounding up or down to the nearest supported font size in the operating system.	Firefox Full support 1 Notes' Full support 1 Notes' Notes' Firefox treats geometricPrecision the same as optimizeLegibility.	IE No support No	Opera Full support 15 Notes' Full support 15 Notes' Notes' Supports true geometric precision without rounding up or down to the nearest supported font size in the operating system.	Safari Full support 6	WebView Android Full support 37 Notes' Full support 37 Notes' Notes' Supports true geometric precision without rounding up or down to the nearest supported font size in the operating system.	Chrome Android Full support 18 Notes' Full support 18 Notes' Notes' Supports true geometric precision without rounding up or down to the nearest supported font size in the operating system.	Firefox Android Full support 46 Notes' Full support 46 Notes' Notes' Firefox treats geometricPrecision the same as optimizeLegibility.	Opera Android Full support 14 Notes' Full support 14 Notes' Notes' Supports true geometric precision without rounding up or down to the nearest supported font size in the operating system.	Safari iOS Full support 6	Samsung Internet Android Full support 1.0 Notes' Full support 1.0 Notes' Notes' Supports true geometric precision without rounding up or down to the nearest supported font size in the operating system.

Legend

Full support  

Full support

No support  

No support

Non-standard. Expect poor cross-browser support.'

Non-standard. Expect poor cross-browser support.

See implementation notes.'

See implementation notes.

See also

• Drawing text in a <canvas>
• CSS Text Decoration CSS module
• Related CSS properties
  • text-decoration (and its longhand properties, such as text-decoration-line, text-decoration-style, and text-decoration-thickness)
  • text-emphasis (and its longhand properties, including text-emphasis-color, text-emphasis-position, and text-emphasis-style)
  • text-shadow
  • text-transform
• The SVG text-rendering attribute
• SVG and CSS

text-rendering by Mozilla Contributors is licensed under CC-BY-SA 2.5.