Definition

Interaction to Next Paint (INP) is a Core Web Vitals metric that measures the latency of click, tap, and keyboard interactions on a page, reporting the longest (or near-longest, on pages with many interactions) as the page's INP value.

INP replaced First Input Delay as a Core Web Vital in March 2024. The thresholds, measured at the 75th percentile of field data, are "good" ≤200ms, "needs improvement" ≤500ms, and "poor" >500ms. INP captures the full latency from input to next paint — including event-handler work, rendering, and presentation — so it reflects the responsiveness users actually experience, unlike FID which only measured input delay.

Examples

• Heavy filter handler on a product list

  A retailer's product listing page runs an expensive filter calculation on each tap of a category chip. CrUX reports an INP of 720ms — the "poor" bucket. Moving the calculation behind a debounced web worker drops INP to 180ms and the page enters "good".

Sources

• web.dev — Interaction to Next Paint (INP)

Related terms

• Core Web Vitals
  A set of three Google metrics that measure real-world page experience: loading speed, interactivity and visual stability.
• Largest Contentful Paint
  A Core Web Vitals metric measuring how long the largest visible content element on a page takes to render after loading begins.

Where QueryCatch uses this

• Page Optimisation