How to Improve Interaction to Next Paint (INP) and Make Your Site Feel Faster
INP measures how quickly your site responds to taps and clicks. Under 200ms is the target. Here is how to fix a sluggish-feeling site.
Reviewed by Jacob Rhinehart for Strelva's co-founder; products and operations lead responsibilities.
Interaction to Next Paint, or INP, measures how quickly your site responds when someone taps, clicks, or types. Under 200 milliseconds feels instant. INP became a Core Web Vital in 2024, replacing the older First Input Delay, and a poor score makes your site feel sluggish or broken even when it loads quickly.
Why INP matters
Load speed gets the visitor in; responsiveness keeps them. If a button takes half a second to react, users tap again, get frustrated, and leave. INP is also a ranking signal, so a slow, janky feel costs you twice. The cause is almost always JavaScript blocking the main thread.
How to fix it
- Measure real interactions. Use PageSpeed Insights field data and the Performance panel's interactions track with CPU throttling on to find which taps are slow.
- Audit third-party scripts. Chat widgets, analytics, and trackers are common offenders. Remove what you do not need and defer the rest.
- Defer non-critical JavaScript. Load scripts that are not needed for the first interaction after the page is interactive, or on demand.
- Optimize event handlers. Give immediate visual feedback (under 50ms) before doing heavy work, and break long tasks into smaller chunks so the browser can stay responsive.
- Reduce bundle and DOM size. Smaller JavaScript and fewer DOM elements both make every interaction cheaper, which matters most on mid-range phones.
Mobile is the real test
Mobile processors are several times slower than desktop, so the same code takes much longer to run. Always test on a real mid-range Android device, not just your fast laptop. Confirm INP is under 200 milliseconds in Search Console field data, and set up real-user monitoring to catch regressions over time.
Frequently asked
What business owners ask next.
What is a good INP score?
Under 200 milliseconds is good, 200 to 500 needs improvement, and over 500 is poor. INP is measured from real user interactions, so optimize for mid-range mobile devices, which is where most problems appear.
Why is my INP fine on desktop but bad on mobile?
Mobile processors run JavaScript several times slower than desktop. The same handlers and scripts that feel instant on a laptop block the main thread on a phone. Reduce bundle size and defer third-party scripts to fix it.