INP: the speed score that measures whether your site feels broken.

Most conversations about website speed are about loading: how long before the page appears. But visitors judge a site just as much by what happens next. They tap a menu, open a filter, press Add to cart, and either it responds straight away or there is a pause that makes them tap again. That pause has a name and a score.

What INP measures

Interaction to Next Paint (INP) became one of Google's Core Web Vitals in March 2024, replacing First Input Delay. It watches the clicks, taps and key presses during a visit and reports how long the page took to visibly respond, using close to the slowest interaction (Google ignores a few outliers on busy pages). Scrolling and hovering are not counted.

• Good: 200 milliseconds or less.
• Needs improvement: over 200 and up to 500 milliseconds.
• Poor: over 500 milliseconds.
• Measured at the 75th percentile of real visits, separately for mobile and desktop.

Where the time goes

Every interaction has three parts, and a slow one is usually slow in one of them. Input delay is the wait before your code can even start, often because the browser is busy with something else. Processing time is your own code running in response. Presentation delay is the time to draw the result on screen.

• Heavy third-party scripts, such as chat widgets, trackers and tag managers loading everything at once, often cause input delay. Load what you need, when you need it.
• Long tasks block everything. Break big pieces of work into smaller chunks so the page can respond in between.
• Large, deeply nested pages make every update slower to draw. Simpler layouts and fewer elements help directly.
• Show feedback immediately, then do the slower work. A button that changes state at once feels fast even if the result takes a moment.

How to check your own site

Start with field data from real visitors, not a single lab test. The Core Web Vitals report in Search Console and PageSpeed Insights both show INP from real Chrome users where there is enough traffic. Page experience is also one of the basics behind SEO, GEO and AEO. Then reproduce the slow interactions yourself on a mid-range phone, which is what many of your visitors use, while the page is still loading and along the paths people actually take.

Good INP is rarely about one clever trick. It comes from a lean build, careful use of third-party scripts and testing on real phones. It is cheaper to design in from the start than to fix after launch, which is why we check it before every site goes live. You can try the sites we have built on our work page.