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 · Desktop 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
48ms
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 · desktop 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
none47ms21% of sites
deflate47ms0% of sites
gzip48ms46% of sites
br52ms28% of sites
zstd52ms5% of sites
VariantShare of sitesMedian
none 38,855 sites
21%
47ms
deflate 86 sites
0%
47ms
gzip 85,313 sites
46%
48ms
br 51,735 sites
28%
52ms
zstd 9,264 sites
5%
52ms

Little daylight between the groups: every variant sits near 47ms median INP. computed

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

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

VariantSitesPassing INPINP
Deflate 0% 86 100% 47ms
Zstd 5% 9,264 99% 52ms
Gzip 46% 85,313 99% 48ms
Br 27.9% 51,735 99% 52ms
None 21% 38,855 99% 47ms
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 99% and 99%. computed

The State of Web Vitals · Q2 2026 · 189,915 sites · desktop 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, 88% of sites pass the LCP. With Zstd, 83% 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