Interaction to Next Paint (INP)
A responsiveness metric that measures the delay between a user action and the visual response. Replaced FID in 2024.
In brief
INP (Interaction to Next Paint) is a Core Web Vitals metric that assesses a page‘s responsiveness to all user interactions (clicks, taps, keyboard input) throughout the entire visit. A low INP means the page responds quickly to actions, providing smooth interactivity.
What is Interaction to Next Paint
INP measures the delay between a user interacting with a page (e.g., clicking a button or typing) and the browser painting the next frame that visually confirms that interaction. INP considers all interactions, not just the first, providing a fuller picture of responsiveness.
Thresholds
- Good: ≤ 200 ms
- Needs Improvement: 200–500 ms
- Poor: > 500 ms
How to improve INP
- Reduce JavaScript: remove unused code, use code splitting, tree shaking.
- Optimise event handlers: apply debounce and throttle to frequent events (scroll, resize, text input).
- Move heavy computations to Web Workers.
- Avoid long tasks: break them using setTimeout or requestIdleCallback.
- Remove or defer third‑party scripts (widgets, chats, analytics) that are not critical for interaction.
INP became an official Core Web Vitals metric in March 2024, replacing FID. Ensure your monitoring tools (Lighthouse, PageSpeed Insights, CrUX) are updated. Google considers INP for ranking.
FAQ
Common questions
FID measured only the delay of the first click after page load. INP measures all interactions throughout the user‘s entire visit, giving a fuller picture of responsiveness.
Yes, as part of Core Web Vitals, which are Google ranking factors (especially for mobile search).
Use Google PageSpeed Insights, the Core Web Vitals report in GSC, Chrome DevTools (Performance panel), or lab tools like WebPageTest.
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