What Is INP?
INP (Interaction to Next Paint) measures the delay between a user's interaction with a page (a click, keyboard input, or touch) and the moment the browser renders the next frame with the resulting update.
Thresholds:
- Good: < 200ms
- Needs Improvement: 200-500ms
- Poor: > 500ms
INP vs. FID
| Metric | What It Measures | How the Value Is Derived |
|---|---|---|
| FID (deprecated) | First input delay | Takes the first interaction |
| INP (new metric) | Delay across all interactions | Takes the 98th percentile of all interactions |
INP is stricter: instead of looking only at the first click, it monitors the response latency of every interaction throughout the entire visit.
Common INP Problems and How to Fix Them
Problem 1: Long Tasks blocking the main thread
- Cause: Large blocks of JavaScript execution that can't be interrupted
- Fix: Break long tasks into multiple smaller tasks
Problem 2: Framework rendering performance issues
- Cause: Frameworks like React/Vue trigger heavy re-renders on state updates
- Fix: Use optimization hooks such as useMemo and useCallback
How to Measure INP
- Lab measurement: The Performance panel in Chrome DevTools, or Lighthouse
- Real-user data: The Core Web Vitals report in Google Search Console (recommended)
We recommend using the technical SEO tools in our SEO Tools Directory for a comprehensive diagnosis.