The State of Web Vitals

A/B testing impact

Performance impact by ab_testing provider.

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

At a glance the headline numbers for A/B testing impact

Performance impact by ab_testing provider.

7
Providers ranked
After min-sites filter
11,168
Sites in sample
Combined across all items
0.03
Best CLS (p75)
Google Optimize
The State of Web Vitals · Q1 2026 · 94,910 sites · phone field datacorewebvitals.io/state-of-cwv
2

The ranking sorted by CLS at p75, fastest first

# Provider CLS p75 Passing Sites
1 Google Optimize 0.03 87.4%
10,546
2 VWO 0.05 83.1%
246
3 Kameleoon 0.07 75.9%
60
4 Optimizely 0.09 76.0%
82
5 Convert 0.09 78.1%
105
6 AB Tasty 0.12 72.1%
53
7 LaunchDarkly 0.15 68.5%
76
The State of Web Vitals · Q1 2026 · 94,910 sites · phone field datacorewebvitals.io/state-of-cwv
3

Passing CLS per provider which group passes the CLS most often

ProviderSitesPassing CLSp75
Google Optimize 11.1% 10,546 87% 0.03
VWO 0.3% 246 83% 0.05
Monetate 0% 13 82% 0.05
Convert 0.1% 105 78% 0.09
Optimizely 0.1% 82 76% 0.09
Kameleoon 0.1% 60 76% 0.07
AB Tasty 0.1% 53 72% 0.12
LaunchDarkly 0.1% 76 69% 0.15
Dynamic Yield 0% 37 63% 0.17
Split.io 0% 5 33% 0.16
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

87% of Google Optimize sites pass CLS. Convert trails 9 points behind. computed

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

All five vitals at once the whole category without toggling - cell is the pass rate, small number the p75

LCP
INP
CLS
FCP
TTFB
Google Optimize 11.1%
812.2s
93126ms
870.03
741.8s
541.2s
VWO 0.3%
772.4s
74204ms
830.05
721.9s
511.2s
Convert 0.1%
662.7s
78196ms
780.09
712.0s
521.5s
Optimizely 0.1%
652.9s
64252ms
760.09
612.1s
491.2s
LaunchDarkly 0.1%
483.9s
63258ms
690.15
463.0s
561.1s
Kameleoon 0.1%
762.5s
57254ms
760.07
721.8s
481.2s
AB Tasty 0.1%
792.2s
74198ms
720.12
771.7s
60911ms
Dynamic Yield 0%
593.0s
41310ms
630.17
662.1s
531.3s
Monetate 0%
732.4s
70194ms
820.05
821.7s
46943ms
Split.io 0%
672.9s
100150ms
330.16
672.3s
100559ms
60%95%+ passing Cell: pass rate, small number = p75 · faded rows: under 100 sites

One row per provider, one column per vital - the cell is the share of sites passing, the small number the p75. No toggling needed to see where the category actually differs.

Google Optimize leads on CLS: 87% of its sites pass. Convert trails at 78%. computed

The State of Web Vitals · Q1 2026 · 94,910 sites · phone field datacorewebvitals.io/state-of-cwv
Related signals Maps (4) → CDN (15) → Chat & messaging (16) → Bot detection (7) → Chrome field data from 94,910 sites, representing millions of real page loads · How we measured