Document doesn't use legible font sizes
Font sizes smaller than 12px are often difficult to read on mobile devices, and may require users to pinch-to-zoom in order to display the text at a comfortable reading size. Lighthouse flags pages with illegible font sizes:
What causes this audit to fail
When a page fails the audit, Lighthouse lists the results in a table with 4 columns:
- Source. The source location of the CSS ruleset that is causing the illegible text.
- Selector. The selector of the ruleset.
- % of Page Text. The percentage of text on the page that is affected by the ruleset.
- Font Size. The computed size of the text.
Each SEO audit is weighted equally in the Lighthouse SEO Score, with the exception of the manual audit, structured-data audit. Learn more in Lighthouse Scoring Guide.
How to fix illegible fonts
Aim to have a font size of at least 12px on at least 60% of the text on your pages. Learn more in Fix small font sizes.
Text is illegible because of a missing viewport config
If Lighthouse reports Text is illegible because of a missing viewport config,
add a <meta name="viewport" content="width=device-width, initial-scale=1"> tag
to the <head> of your document.
See also Has a <meta name="viewport"> tag with width or initial-scale.
More information
Illegible font sizes audit source
Except as otherwise noted, the content of this page is licensed under the Creative Commons Attribution 4.0 License, and code samples are licensed under the Apache 2.0 License. For details, see the Google Developers Site Policies. Java is a registered trademark of Oracle and/or its affiliates.