The State of Web Vitals

LCP responsive markup

Responsive markup on the LCP image: srcset, picture, or none.

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

At a glance the headline numbers for LCP responsive markup

Responsive markup on the LCP image: srcset, picture, or none.

3
Categories
90,431 sites
78.5%
Top share
no
0.03
Top CLS
Median for no

78.5% of LCP images ship without responsive markup.

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

LCP responsive markup who uses what, and how stable each group is

Median CLS
0
0.05
0.10
0.15
0.20
0.25
srcset0.0214% of sites
no0.0379% of sites
picture0.037% of sites
VariantShare of sitesMedian
srcset 12,828 sites
14%
0.02
no 71,021 sites
79%
0.03
picture 6,582 sites
7%
0.03

Little daylight between the groups: every variant sits near 0.02 median CLS. computed

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

Passing CLS per LCP responsive markup which group passes the CLS most often

VariantSitesPassing CLSCLS
Srcset 14.2% 12,828 81% 0.02
No 78.5% 71,021 78% 0.03
Picture 7.3% 6,582 76% 0.03
Good Needs Improvement Poor Sorted best-passing first · median colored by its own rating · pass = good CLS (0.1 at p75) · one value per site

81% of Srcset sites pass CLS. Picture trails 5 points behind. computed

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

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

A phone should not download the desktop hero. srcset and picture let the browser pick the file that fits the viewport, which directly cuts the LCP's load time on small screens. Without them, every device downloads the largest image someone uploaded.

The win is biggest exactly where LCP is hardest: small screens on slow connections. Most CMSs generate the size candidates automatically. The gaps are usually hand-written templates and page builders.

How does this affect the Core Web Vitals?

LCP responsive markup correlates with the LCP. With Picture, 91% of sites pass the LCP. With No, 85% do.

Go fix it Optimize images for Core Web Vitals → Optimize the LCP image → Fix slow hero images →
Related signals LCP priority hint → LCP discovery → LCP image size → LCP origin → Chrome field data from 94,910 sites, representing millions of real page loads · How we measured