Interaction to Next Paint

Interaction to Next Paint, or INP, measures responsiveness: how long it takes from a click, tap or key press until the page visibly responds. It observes the interactions during a visit and reports one of the slowest, ignoring a small number of outliers on pages with many interactions. Good is 200 milliseconds or less, needs improvement is up to 500 milliseconds and poor is above 500 milliseconds, assessed at the 75th percentile of page loads. INP replaced First Input Delay (FID) as a Core Web Vital in March 2024, because FID only measured the delay before the first interaction started being handled.

Poor INP feels like a page that is stuck. A visitor taps a menu, a tab or a form field and nothing happens, so they tap again or give up. The cause is almost always JavaScript keeping the browser's main thread busy: heavy page builders, chat widgets, tracking scripts, sliders and large frameworks doing a lot of work at once.

INP can only be measured accurately with real users, because it depends on what people actually do. Lab tools like Lighthouse cannot measure it directly; they report total blocking time instead, which shows how much the main thread is blocked during loading and is a useful indicator of likely responsiveness problems.

How to improve it

• Check the field INP for your page in Google PageSpeed Insights or Search Console, if enough data is available.
• Remove third-party scripts and widgets you do not really need on the landing page.
• Delay non-essential scripts such as chat and tracking until after the page has loaded or the user interacts.
• Break long JavaScript tasks into smaller pieces so the browser can respond in between.
• Keep the page's HTML small and avoid heavy animations triggered by interactions.

How PageScore checks it

PageScore does not measure real-user INP from your analytics. It reports total blocking time from a Google PageSpeed Insights mobile test, a lab metric that flags the main-thread work that usually causes poor INP.