Stylesheets per page
How many stylesheets the page loads and their over-the-wire weight.
At a glance the headline numbers for Stylesheets per page
How many stylesheets the page loads and their over-the-wire weight.
The typical page loads 15 stylesheets weighing 77 KB.
Distribution & median INP site count and median INP at each level of stylesheets per page — n
Passing INP by stylesheets per page — n which level passes the INP most often
Stylesheets per page — n 15. p75 31. p99 119. At the low end (0): INP 46ms. At the high end (>p98): INP 62ms. computed
Distribution & median INP site count and median INP at each level of stylesheets per page — size
Passing INP by stylesheets per page — size which level passes the INP most often
Stylesheets per page — size 77 KB. p75 153 KB. p99 1.2 MB. At the low end (0 KB): INP 57ms. At the high end (>p98): INP 49ms. computed
Why this matters for the Core Web Vitals, and where to start fixing it
Every blocking stylesheet is a render gate. The browser paints nothing until the last one arrives, so the count multiplies the risk: more requests on the critical path, more chances that one of them is the slow one.
Few files beat many here. The request side costs more than the byte side: one round trip on a cold connection outweighs a lot of kilobytes on a warm one. Bundle the critical CSS into as few files as the architecture allows.
How does CSS affect the Core Web Vitals?
Stylesheets per page correlates with the LCP. Stylesheet count separates passing sites from failing sites more than CSS weight does. Where the stylesheet count is low, 86% of sites pass the LCP. Where it is high, 75% do. The decline is gradual. There is no point where sites suddenly start failing.
Chrome field data from 94,910 sites, representing millions of real page loads. How we measured.