INP (Interaction to Next Paint) is a Core Web Vitals metric that evaluates the time it takes for all user interactions on a page (clicks, taps, keyboard input) to be processed by the browser and produce a visual result on the screen. It replaced FID in March 2024.
Target values:
- Good: below 200 ms
- Needs improvement: 200 – 500 ms
- Poor: above 500 ms
Unlike FID, INP evaluates the entire page lifecycle, and the worst interaction at the 75th percentile is typically reported. Therefore, even a single slow interaction can hurt the score.
To improve INP:
- Break up long JavaScript tasks (yieldToMain pattern)
- Remove unnecessary work from event handlers
- Lazy-load or defer third-party scripts
- Move render-blocking work to a Web Worker
Tip: Track INP with real user data (Search Console or CrUX); lab tests often do not reveal INP.