WordPress main-thread CPU breakdown and the Core Web Vitals

35.1% of audited sites (22,247) spend over 1,200ms in main-thread scripting during load, pushing median field INP to 92ms (97% good INP) versus 82ms (99% good INP) at 150 to 450ms.

Field data PhoneDesktopAll Scope All sites October 2026 edition · All devices field outcomes · WordPress sites only
WordPress Scoped to 63,295 sites out of 203,892 analyzed (cms) Compare with all sites →

29.4% of WordPress sites use 450 to 1,200ms of scripting CPU main-thread CPU breakdown, and 99% of those sites have a good INP, against 98% of all WordPress sites.

The State of Web Vitals · October 2026 · WordPress: 63,295 crawled sites · 60,855 with all devices field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
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INP pass rate

Sites with 450 to 1,200ms of scripting CPU main-thread CPU breakdown have a good INP most often: 99%, against 98% of all WordPress sites. Sites with over 1,200ms of scripting CPU scripting CPU have it least often, at 97%.

SitesGood, needs improvement, poor INPMedian
All WordPress sites60,85598%86ms
450 to 1,200ms scripting CPU 29.4%17,96699%86ms
150 to 450ms scripting CPU 21.0%12,70599%82ms
Under 150ms scripting CPU 14.4%8,66898%77ms
Over 1,200ms scripting CPU 35.1%21,51697%92ms
GoodNeeds improvementPoorSites: with Chrome field data
The State of Web Vitals · October 2026 · WordPress: 63,295 crawled sites · 60,855 with all devices field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
2

Main-thread CPU breakdown usage

Over 1,200ms of scripting CPU is the most used: 35.1% of WordPress sites. 450 to 1,200ms of scripting CPU is 29.4% of WordPress sites.

Over 1,200ms scripting CPU 35.1% 450 to 1,200ms scripting CPU 29.4% 150 to 450ms scripting CPU 21.0% Under 150ms scripting CPU 14.4%
Over 1,200ms scripting CPU 35.1% 450 to 1,200ms scripting CPU 29.4% 150 to 450ms scripting CPU 21.0% Under 150ms scripting CPU 14.4%
The State of Web Vitals · October 2026 · WordPress: 63,295 crawled sites · 60,855 with all devices field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
3

Main-thread CPU breakdown per framework

On jQuery, 36% of sites use over 1,200ms of scripting CPU main-thread CPU breakdown, and 98% of jQuery sites have a good INP, against 98% of all sites. On Vue, 41% of sites use over 1,200ms of scripting CPU, and 97% of Vue sites have a good INP.

FrameworkMain-thread CPU breakdown on its sitesGood INP
All WordPress sites 63,295 sitesOver 1,200ms scripting CPU 35%450 to 1,200ms scripting CPU 29%150 to 450ms scripting CPU 21%Under 150ms scripting CPU 14%98%
React 2,233 sitesOver 1,200ms scripting CPU 47%450 to 1,200ms scripting CPU 28%150 to 450ms scripting CPU 17%98%
jQuery 60,314 sitesOver 1,200ms scripting CPU 36%450 to 1,200ms scripting CPU 30%150 to 450ms scripting CPU 21%Under 150ms scripting CPU 13%98%
Vue 4,844 sitesOver 1,200ms scripting CPU 41%450 to 1,200ms scripting CPU 32%150 to 450ms scripting CPU 20%97%
Alpine 380 sitesOver 1,200ms scripting CPU 35%450 to 1,200ms scripting CPU 34%150 to 450ms scripting CPU 22%95%
Over 1,200ms scripting CPU 450 to 1,200ms scripting CPU 150 to 450ms scripting CPU Under 150ms scripting CPU
The State of Web Vitals · October 2026 · WordPress: 63,295 crawled sites · 60,855 with all devices field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
4

Main-thread CPU breakdown or the framework

Does the framework explain the main-thread CPU breakdown difference?

On jQuery, 99% of sites with 450 to 1,200ms of scripting CPU main-thread CPU breakdown have a good INP, against 97% of jQuery sites with over 1,200ms of scripting CPU. Within jQuery, sites with 450 to 1,200ms of scripting CPU have a good INP more often. On Vue, 98% of sites with 450 to 1,200ms of scripting CPU main-thread CPU breakdown have a good INP, against 96% of Vue sites with over 1,200ms of scripting CPU. Within Vue, sites with 450 to 1,200ms of scripting CPU and over 1,200ms of scripting CPU have a good INP about equally often.

Why scripting dominates main-thread CPU budgets

Across the web, JavaScript evaluation accounts for the largest share of total main-thread CPU time, dwarfing HTML parsing, style calculation, and painting. Across 13,281 sites (21.0%) spending 150 to 450ms in scripting CPU, 99% pass field INP (82ms median), while the 35.1% (22,247) exceeding 1,200ms drop to 97% good INP (92ms median).

The State of Web Vitals · October 2026 · WordPress: 63,295 crawled sites · 60,855 with all devices field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
5

Understanding main-thread CPU breakdown

Delay non-essential third-party tag managers, ad scripts, and chat widgets so initial scripting CPU stays below 450ms. On WordPress, 21.0% of sites spend 150 to 450ms in scripting CPU (99% good INP) while 35.1% exceed 1,200ms (97% good INP).

The State of Web Vitals · October 2026 · WordPress: 63,295 crawled sites · 60,855 with all devices field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
Related signals Document lifecycle (lab) → Lab paint timeline → Total Blocking Time (lab) → By Arjen Karel · 63,295 crawled WordPress sites (60,855 with all devices Chrome field data, October 2026) · How we measured