The State of Web Vitals

HTML compression

Compression on the HTML document: brotli, gzip, or none.

Field data PhoneDesktopAll Scope All sites Q2 2026 edition · Phone field outcomes
Metric LCP INP CLS
1

At a glance the headline numbers for HTML compression

Compression on the HTML document: brotli, gzip, or none.

8
Categories
185,262 sites
46.0%
Top share
gzip
97ms
Top INP
Median for gzip

27.9% of HTML documents are Brotli-compressed. 21.0% ship raw.

The State of Web Vitals · Q2 2026 · 189,915 sites · phone field datacorewebvitals.io/state-of-cwv
2

HTML compression who uses what, and how fast each group loads

Median INP
0
100ms
200ms
300ms
400ms
500ms
gzip97ms46% of sites
br100ms28% of sites
none100ms21% of sites
zstd106ms5% of sites
deflate118ms0% of sites
VariantShare of sitesMedian
gzip 85,313 sites
46%
97ms
br 51,735 sites
28%
100ms
none 38,855 sites
21%
100ms
zstd 9,264 sites
5%
106ms
deflate 86 sites
0%
118ms

Little daylight between the groups: every variant sits near 97ms median INP. computed

The State of Web Vitals · Q2 2026 · 189,915 sites · phone field datacorewebvitals.io/state-of-cwv
3

Passing INP per HTML compression which group passes the INP most often

VariantSitesPassing INPINP
Deflate 0% 86 94% 118ms
Gzip 46% 85,313 93% 97ms
Br 27.9% 51,735 92% 100ms
Zstd 5% 9,264 89% 106ms
None 21% 38,855 89% 100ms
Good Needs Improvement Poor Sorted best-passing first · median colored by its own rating · pass = good INP (200ms at p75) · one value per site

No variant stands out: pass rates sit between 89% and 93%. computed

The State of Web Vitals · Q2 2026 · 189,915 sites · phone field datacorewebvitals.io/state-of-cwv
4

Why this matters for the Core Web Vitals, and where to start fixing it

The HTML document is the first thing the browser reads, and the sooner the markup arrives, the sooner the preload scanner can discover everything else: the stylesheets, the fonts, the LCP image. Brotli and gzip shrink HTML to a fraction of its raw size. None means the visitor downloads every byte of markup before the page can even start discovering resources.

Brotli compresses tighter than gzip and every major CDN offers it. This is a switch, not a project.

How does this affect the Core Web Vitals?

HTML compression correlates with the LCP. With Br, 86% of sites pass the LCP. With Zstd, 78% do.

Go fix it Configure Cloudflare for passing the Core Web Vitals → Compression mix →
Related signals HTTP protocol mix → Connection hints → Cache strategy mix → Uncompressed text responses → Chrome field data from 189,915 sites, representing millions of real page loads · How we measured