Interaction to Next Paint (INP) Test

SEOptimer's Interaction to Next Paint test shows your page's INP against Google's thresholds, using Google's own field data from real visitors.

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About Interaction to Next Paint

What is Interaction to Next Paint?

Interaction to Next Paint measures how long a page takes to visibly respond when someone interacts with it - a tap, a click, a key press. It runs from the moment of the interaction to the moment the screen next updates.

What it captures is the feeling of a page being unresponsive: the menu that does not open, the button pressed twice because nothing happened the first time. That delay is almost always the main thread being busy with something else.

It became a Core Web Vital in March 2024, replacing First Input Delay. The change mattered because the old metric measured only the delay before the first interaction started processing, which flattered pages that responded promptly once and then bogged down.

What counts as a good INP?

Google treats 200 milliseconds or less as good, 200 to 500 milliseconds as needing improvement, and anything beyond 500 milliseconds as poor, again at the 75th percentile of real interactions.

Unlike LCP, this is not one measurement per page load. A visitor interacts many times in a session, and INP reports close to the worst of those, so a page is judged on its slowest moment rather than its typical one.

That makes it the hardest of the three to fake. A page can be made to load quickly for a test; staying responsive through a whole session is a property of how it is built.

What usually causes a poor INP

INP problems are nearly always JavaScript problems, and specifically long tasks blocking the main thread when the visitor is trying to use the page.

Heavy event handlers doing their work synchronously before yielding.
Large scripts still parsing and executing while the page looks ready.
Third-party tags - chat widgets, analytics, A/B testing, ad scripts - competing for the same thread.
Expensive layout work triggered by an interaction, such as re-rendering a long list.
Frameworks re-rendering more of the page than the interaction actually changed.

Third parties deserve particular suspicion, because they are the part of the page nobody owns and the part that changes without anyone deploying anything.

How to improve it

Break long tasks up and yield to the browser so it can paint between them.
Show the visible result of an interaction first, then do the remaining work.
Defer anything not needed for the first interaction, third-party scripts especially.
Audit the tag manager. Most sites carry tags nobody has needed for years.
Avoid re-rendering whole sections when one element changed.
Test on a mid-range phone, where the thread is far easier to saturate than on a laptop.

What this tool checks

The INP test reads Google's field data for the page - measurements collected from real visitors in Chrome - and shows where it falls against the thresholds above.

INP can only be measured when somebody actually interacts, so it is the metric most likely to be unavailable on a quiet page or one people simply read. That is not a failure; it means there is nothing to report yet.

For the other two metrics, or all three together, use the Core Web Vitals test.

Where to go next

Responsiveness is a scripting problem, so start with what the page is running. Check for JavaScript errors, see how many separate files it pulls in with the page request tool, and confirm nothing is broken outright with a full site audit.

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