What Is INP? Interaction to Next Paint Explained

In plain English

It replaced First Input Delay, which only measured the first interaction and only the delay before processing began. INP looks at interactions throughout the visit and measures until something visibly changes.

That makes it a much harder test, and a much more honest one. It captures the pages that load quickly and then feel sluggish to use.

What to know

What is measured

The time from an interaction until the next visual update, across the visit.

Target

Under 200 milliseconds for most interactions.

Usual cause

Too much JavaScript occupying the main thread.

Fixes

Reduce and defer scripts, break up long tasks, remove unused third-party tags.

Why it matters

INP is where heavy tag managers, chat widgets and tracking scripts show up as a real cost. It is the vital that most often catches sites that look fast in a page speed test but feel unresponsive to a real user.

Common mistakes

×Adding third-party scripts without measuring the cost.

×Assuming a good LCP means the page feels fast.

×Treating it as a front-end styling problem rather than a JavaScript problem.

×Testing only on a fast desktop machine.

FAQs

What is a good INP?

Under 200 milliseconds. Above 500 is poor.

Did this replace FID?

Yes. INP measures more interactions and measures them more completely.

WRITTEN BY TARIQ SALLAM

Marketing Consultant. Entrepreneur. Content Creator.

I'm a marketing consultant, entrepreneur and content creator. I help businesses grow through practical marketing, websites, SEO, content and AI.

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