Interaction to Next Paint (INP)
How long the page takes to visually respond after a user interacts — the latency between a tap, click, or keypress and the next frame the browser paints.
Vanity Risk
INP is a near-worst-case metric by design — averaging it away defeats its purpose. A "good" mean interaction time with a poor P75 means a meaningful share of visitors hit a janky interaction; that is the experience that drives them away, not the average they never noticed.
What it measures
Responsiveness. INP observes every click, tap, and key press in a session and reports a value near the worst one — the single laggy interaction a visitor remembers. It replaced First Input Delay as a Core Web Vital in 2024 because it captures the whole session, not just the first interaction. High INP is the technical signature of a page that feels janky: the user did something and the interface didn’t answer quickly.
Benchmarks
- Good: ≤ 200ms at P75
- Needs improvement: 200ms–500ms at P75
- Poor: > 500ms at P75
- Thresholds: Google web.dev Core Web Vitals (field data, 75th percentile)
Figures reviewed June 2026. Benchmarks vary by source and drift over time — treat as directional and verify against your own data.
What to watch
- Above 200ms at P75: The main thread is busy when users try to interact. Long tasks from heavy JavaScript, large hydration payloads, and unoptimized event handlers are the common causes. Profile the interactions with the worst latency, not the average.
- Worse on content-heavy routes: Pages with large DOMs or many third-party widgets serialize interaction handling behind layout and script work. Per-route INP isolates which templates are the problem.
- Correlates with rage clicks: When a tap doesn’t respond, users tap again. A spike in repeated rapid clicks alongside high INP is the same problem seen from the behavioral side.
In practice
An interactive pricing configurator had INP at 540ms at P75. Every slider change triggered a synchronous recalculation across the whole DOM. Debouncing the recompute and moving the heavy math off the main thread brought INP to 170ms. Support tickets describing the tool as "frozen" or "broken" stopped within the week — the logic had always been correct; it just hadn’t felt responsive.
Illustrative scenario — a representative composite, not a specific company.
Related: Largest Contentful Paint — LCP is load responsiveness, INP is interaction responsiveness; a page can pass one and fail the other.; Engagement Score — unresponsive pages depress session depth; INP is often the hidden cause behind a falling engagement composite.; Bounce Rate — an interface that doesn’t respond to the first interaction is a leading cause of immediate exits.