The State of Web Vitals

Speculation posture

The strongest speculation rule the document declares: none, prefetch, prerender-until-script, prerender.

Field data PhoneDesktopAll Scope All sites Q1 2026 edition · Phone field outcomes
Metric LCP INP CLS
1

At a glance the headline numbers for Speculation posture

The strongest speculation rule the document declares: none, prefetch, prerender-until-script, prerender.

4
Categories
94,890 sites
65.0%
Top share
none
1.4s
Top LCP
Median for none

65.0% of sites declare no speculation rules at all.

The State of Web Vitals · Q1 2026 · 94,910 sites · phone field datacorewebvitals.io/state-of-cwv
2

Speculation posture who uses what, and how fast each group loads

Median LCP
0
0.5s
1s
1.5s
2s
2.5s
3s
3.5s
4s
prerender_until_script1.1s0% of sites
none1.4s65% of sites
prerender1.7s1% of sites
prefetch1.9s34% of sites
VariantShare of sitesMedian
prerender_until_script 269 sites
0%
1.1s
none 61,678 sites
65%
1.4s
prerender 478 sites
1%
1.7s
prefetch 32,465 sites
34%
1.9s

Prerender_until_script sites post the best median LCP (1.1s). Prefetch sites trail at 1.9s. Correlation, not causation. computed

The State of Web Vitals · Q1 2026 · 94,910 sites · phone field datacorewebvitals.io/state-of-cwv
3

Passing LCP per speculation posture which group passes the LCP most often

VariantSitesPassing LCPLCP
Prerender until script 0.3% 269 94% 1.1s
None 65% 61,678 86% 1.4s
Prerender 0.5% 478 75% 1.7s
Prefetch 34.2% 32,465 73% 1.9s
Good Needs Improvement Poor Sorted best-passing first · median colored by its own rating · pass = good LCP (2.5s at p75) · one value per site

94% of Prerender until script sites pass LCP. Prefetch trails 21 points behind, leaving 27% of its sites failing. computed

The State of Web Vitals · Q1 2026 · 94,910 sites · phone field datacorewebvitals.io/state-of-cwv
4

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

Speculation rules let the browser start the next navigation before the click. Prefetch downloads the next document ahead of time. Prerender goes further and builds the whole next page in a hidden renderer, so navigating to it is a swap instead of a load. Prerender-until-script is the cautious middle: build the page, hold the scripts.

Done right, the next page's LCP is near-instant because it painted before the visitor arrived. The cost is speculative work: prerendering pages nobody visits burns server and client resources. That trade is what eagerness controls.

How does this affect the Core Web Vitals?

Speculation posture correlates with the LCP. With None, 86% of sites pass the LCP. With Prefetch, 73% do. The causal link is weak: the choice mostly marks what kind of site made it.

Go fix it Speculation rules → The prerender-until-script speculation rule → View transitions and web performance →
Related signals Speculation eagerness → Chrome field data from 94,910 sites, representing millions of real page loads · How we measured