coderef

cap unitBaseline · Widely available

The cap CSS length unit corresponds to the height of Latin capital letters.

Supported in all major browsers for at least 30 months — safe to use without fallbacks. Baseline since Dec 11, 2023. Widely available since Jun 11, 2026.

How to use ↓Compare browsers

Browser support

DesktopChrome
1–117Not supported
118+Supportedsince Oct 10, 2023
Current: 155
Edge
12–117Not supported
118+Supportedsince Oct 13, 2023
Current: 154
Firefox
1–96Not supported
97+Supportedsince Feb 8, 2022
Current: 157
Safari
1–17.1Not supported
17.2+Supportedsince Dec 11, 2023
Current: 27
MobileChrome Android
18–117Not supported
118+Supportedsince Oct 10, 2023
Current: 155
Firefox Android
4–96Not supported
97+Supportedsince Feb 8, 2022
Current: 157
Safari iOS
1–17.1Not supported
17.2+Supportedsince Dec 11, 2023
Current: 27

How to use

This feature is Baseline widely available — use it freely, no fallback needed.

Example

Full syntax and examples are on MDN — see the links below.

Feature detection

There’s no simple runtime check for this feature; rely on the support table and test in your target browsers.

Specification