CSS rendering hints (will-change, aspect-ratio, containment) and the Core Web Vitals
will-change (75.4%), aspect-ratio (67.1%), scroll-driven animations (33.7%), CSS containment (29.0%), and content-visibility (26.2%) across 137,494 sites.
75.4% of sites use will-change CSS rendering hints, and 99% of those sites have a good INP, against 99% of all sites.
INP pass rate
Sites with will-change CSS rendering hints have a good INP most often: 99%, against 99% of all sites. Sites with CSS containment CSS hints have it least often, at 99%.
CSS rendering hints usage
Will-change is the most used: 75.4% of sites.
Understanding CSS rendering hints
How CSS rendering hints isolate layout and compositor work
CSS hints instruct the rendering engine how to allocate compositor layers and skip offscreen layout work. Among hint-using sites, 75.4% use will-change (99% good INP), 67.1% use aspect-ratio (99% good INP), 33.7% use scroll-driven animations (99% good INP), 29.0% use contain (99% good INP), and 26.2% use content-visibility (99% good INP).
Use aspect-ratio to reserve responsive media boxes, scroll-driven animations to move scroll effects off the main thread, and content-visibility: auto with contain-intrinsic-size on long below-the-fold sections. Avoid applying will-change across large numbers of elements, which exhausts GPU memory.
How CSS rendering hints plays out per platform
What the field data shows when you isolate a single CMS or framework.
WordPress 53,180 sites WordPress sites using CSS hints include will-change on 84.7% and content-visibility on 37.4%.
Across 53,180 WordPress sites using CSS hints, 84.7% use will-change, 67.6% use aspect-ratio, and 37.4% use content-visibility (100% good INP).
Shopify 8,484 stores Shopify storefronts using CSS hints include scroll-driven animation rules on 97.3% and aspect-ratio on 63.9%.
Across hint-using Shopify storefronts, 97.3% include CSS scroll-driven animation rules (99% good INP), 65.3% use will-change, and 63.9% use aspect-ratio.
React & Next.js 9,068 sites Hint-using React sites include scroll-driven CSS on 77.2% and will-change on 71.3% (99% good INP).
Across 9,068 hint-using React sites, 77.2% include scroll-driven animation rules (99% good INP), 71.3% use will-change, and 53.5% use aspect-ratio.
By Arjen Karel · 210,902 crawled sites (69,745 with desktop Chrome field data, 137,494 sites with CSS rendering hints, October 2026). How we measured.