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Interaction to Next Paint (INP) Test

Check INP against the 200ms threshold — and understand why a lab test alone can never give you one.

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  • No sign-up
  • No limits
  • Instant results
The short version

What is Interaction to Next Paint (INP) Test?

Interaction to Next Paint replaced First Input Delay as a Core Web Vital in March 2024.

It measures the full latency of an interaction — from the tap or click, through the work your JavaScript does, to the next frame the browser actually paints. FID only measured the delay before processing started, which flattered pages that acknowledged a click quickly and then froze. INP is harder to satisfy and much closer to what people mean by "this page feels slow". It is also a field metric: it requires real people interacting, so it can only come from the Chrome UX Report. If your site does not have enough traffic to appear there, INP is genuinely unavailable, and this tool says so rather than showing you a lab number dressed up as one.

Step by step

How to use Interaction to Next Paint (INP) Test

  1. 1

    Enter your page

    INP arrives with the PageSpeed response when the Chrome UX Report has enough data for the URL or its origin.

  2. 2

    If it is unavailable, use Total Blocking Time

    TBT is the lab metric that correlates best with INP. It is not the same measurement, but a high TBT reliably predicts a poor INP.

  3. 3

    Find the long tasks

    INP is usually one slow event handler, not general sluggishness. Profile the interaction that feels worst rather than the page as a whole.

  4. 4

    Break up the work

    Yield to the main thread between chunks, move heavy computation off it, and render the visual acknowledgement before doing the work.

What's inside

Everything this tool
does for you

  • INP from field data where available
  • Honest unavailable state, with the reason
  • Total Blocking Time as the lab proxy
  • Google’s 200ms and 500ms thresholds
  • Free, no signup, no daily limit
Questions

Frequently asked questions

This tool fixed one thing.
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What this tool does
  • INP from field data when your site has it
  • Total Blocking Time shown as the lab proxy that does exist
  • Google’s 200ms / 500ms thresholds
  • Explains plainly when the metric is unavailable
  • Free, no account, no daily limit
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