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.
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.
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%.
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.
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.
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).
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).
By Arjen Karel · 63,295 crawled WordPress sites (60,855 with all devices Chrome field data, October 2026). How we measured.