WordPress main-thread CPU breakdown and the Core Web Vitals

Sites with 450 to 1,200ms of scripting CPU main-thread CPU breakdown have a good INP most often: 100%, against 100% of all WordPress sites. Sites with over 1,200ms of scripting CPU scripting CPU have it least often, at 99%.

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.

On jQuery, 36% of sites use over 1,200ms of scripting CPU main-thread CPU breakdown, and 100% of jQuery sites have a good INP, against 100% of all sites. On Vue, 41% of sites use over 1,200ms of scripting CPU, and 99% 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%100%

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%100%

React 2,233 sitesOver 1,200ms scripting CPU 47%450 to 1,200ms scripting CPU 28%150 to 450ms scripting CPU 17%100%

Vue 4,844 sitesOver 1,200ms scripting CPU 41%450 to 1,200ms scripting CPU 32%150 to 450ms scripting CPU 20%99%

Alpine 380 sitesOver 1,200ms scripting CPU 35%450 to 1,200ms scripting CPU 34%150 to 450ms scripting CPU 22%99%

Over 1,200ms scripting CPU 450 to 1,200ms scripting CPU 150 to 450ms scripting CPU Under 150ms scripting CPU

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

On jQuery, 100% of sites with 450 to 1,200ms of scripting CPU main-thread CPU breakdown have a good INP, against 99% 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, 100% of sites with 450 to 1,200ms of scripting CPU main-thread CPU breakdown have a good INP, against 99% 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, 100% pass field INP (44ms median), while the 35.1% (22,247) exceeding 1,200ms drop to 99% good INP (53ms median).