The State of Web Vitals

CSS hints

CSS performance hints in use: content-visibility, contain, will-change.

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

At a glance the headline numbers for CSS hints

CSS performance hints in use: content-visibility, contain, will-change.

5
Categories
In the distribution
32.9%
Fleet share
Top: will_change
49.2%
Sites with any
Of will_change

12.5% of sites use CSS containment. content-visibility sits at 11.3%.

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

The CSS hints mix who uses what, and how stable each group is

Median CLS (sites using feature)
0
0.10
0.20
0.30
0.40
0.50
Will change0.0033% of sites
Aspect ratio0.0029% of sites
Scroll driven0.0015% of sites
Containment0.0013% of sites
Content visibility0.0011% of sites
VariantShare of sitesMedian
Will change
33%
0.00
Aspect ratio
29%
0.00
Scroll driven
15%
0.00
Containment
13%
0.00
Content visibility
11%
0.00

CSS hints. On the fleet: 32.9% will change, 28.8% aspect ratio, 14.5% scroll driven. 49.2% of sites use at least one will_change.

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

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

These CSS properties limit how far a change can spread. contain declares a subtree self-contained, so a change inside it does not force layout outside it. content-visibility goes further and skips rendering offscreen sections until the visitor approaches them. will-change moves an animated element onto its own layer, so animating it does not repaint the rest of the page.

They attack the DOM problem directly: a big tree hurts because every change can touch all of it, and containment makes updates local. That is exactly what INP needs. will-change is the one to ration. Every promoted layer costs memory, and a blanket will-change makes performance worse, not better.

How does this affect the Core Web Vitals?

The choice barely moves the INP: 93% pass at best, 92% at worst. This signal does not separate passing sites from failing ones.

Go fix it Fix excessive DOM size → HTML reflow and Core Web Vitals → INP: presentation delay →
Related signals Scheduling API use → Interaction invoker types → Yielding strategy → INP phase breakdown → Chrome field data from 189,915 sites, representing millions of real page loads · How we measured