Definition INP is the high-percentile value of all delays generated by clicks, taps, and keyboard interactions. Unlike FID, INP evaluates every interaction across the session, not just the first.
How it works For each interaction, the browser measures input delay, processing time, and presentation delay. Their sum is the interaction's INP. On page unload, the high-percentile (usually 98th) across all interactions is reported as INP. Long JavaScript tasks and large layout reflows raise the value.
Where you see it in Scope Trends The **Core Web Vitals** report shows INP per page. **Site Crawl** outputs the average event handler duration and long task count per page.
Frequently asked questions **INP thresholds?** Good <= 200 ms, needs improvement 200-500 ms, poor > 500 ms.
**What hurts INP most?** Third-party scripts, heavy event handlers, animations that block the main thread, and large React render chains.