INP Optimization: The New Core Web Vital You Can't Ignore
Interaction to Next Paint (INP) has replaced FID. Learn how to measure, debug, and optimize your site's responsiveness for better rankings in 2025.
Google's Core Web Vitals are evolving. Interaction to Next Paint (INP) has officially replaced First Input Delay (FID) as a key ranking factor. Unlike FID, which only measured the first interaction, INP assesses the responsiveness of all interactions on a page. If your site feels "laggy" on mobile, your INP score—and your rankings—will suffer. This guide breaks down exactly how to audit and fix INP issues.
What causes poor INP scores?
Heavy JavaScript execution is the usual suspect. When the main thread is blocked by large scripts, the browser cannot respond to user clicks or taps immediately. Third-party trackers, unoptimized hydration in React/Next.js, and large DOM sizes also contribute.
How to measure INP?
You can use Google Search Console's "Core Web Vitals" report or our own Free Tech Audit Tool to see your real-world field data.
FID vs. INP: Key Differences
| Feature | FID (Old) | INP (New Standard) |
|---|---|---|
| Scope | First interaction only | All interactions |
| Metric | Delay processing | Total visual latency |
| Goal | < 100ms | < 200ms |
⚡ Performance Fact
Improving INP from "Poor" to "Good" can result in a 12-15% increase in mobile conversion rates.
Frequently Asked Questions
- Does INP affect SEO?
Yes, it is now a confirmed ranking signal as part of the Page Experience update. - How do I fix high INP?
Break up long tasks, use web workers, and optimize event callbacks. - Is INP mobile-only?
No, but it is usually more critical on mobile devices due to slower processors.
Test Your INP Score
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