sibling-count() and sibling-index()
The sibling-count() and sibling-index() CSS functions return integers that are useful to style elements based on their positions among siblings or on the number of siblings, for example as part of a calc() expression.
Status
Limited availability
MDN documentation
Specifications
Browser support
- Chrome 138 Released on 2025-06-24
- Chrome Android 138 Released on 2025-06-24
- Edge 138 Released on 2025-06-26
- Firefox ❌ See bugzil.la/1953973 Vendor position : positive
- Firefox for Android ❌ See bugzil.la/1953973 Vendor position : positive
- Safari 26.2 Released on 2025-12-12
- Safari on iOS 26.2 Released on 2025-12-12
Baseline availability blocked since December 2025 by Firefox (1 months)
Developer signals
- State of CSS 2025: usage/favorite_new_features question
- State of CSS 2025: usage/css_missing_features question
- State of CSS 2025: usage/css_interoperability_features question
- State of CSS 2025: reading_list/reading_list question
- State of CSS 2025: other_features/other_features_pain_points question
- State of CSS 2025: math_features/math_features_pain_points question
- State of CSS 2025: features/all_features question
Web Platform Tests (WPT)
View the latest WPT test results for this featureDeveloper signals
Votes: 33
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