INP (Interaction to Next Paint)
INP (Interaction to Next Paint) is a Google Core Web Vitals metric that measures how responsive a web page is to user interactions. It records the delay, in milliseconds, between an action (a click, a tap, a key press) and the moment the browser paints the corresponding visual update on screen. Unlike its predecessor FID, which measured only the first interaction, INP evaluates the latency of every interaction during a visit and reports the slowest one (excluding outliers). It became an official Core Web Vital in March 2024, permanently replacing FID. Google sets the good-responsiveness threshold at 200 ms or less; between 200 and 500 ms the experience needs improvement; above 500 ms it is considered poor. INP is one of the page experience signals Google uses.
INP (Interaction to Next Paint) is a Core Web Vitals metric that measures how quickly a web page responds to user interactions. In practice, it times the gap between a click, a tap or a key press and the moment the browser displays the visual result on screen.
How INP is calculated
For each interaction, the browser measures the total latency: input delay, script processing time and rendering (paint) delay. INP then reports the slowest interaction of the visit, dropping a few extreme values on heavily used pages. The measurement relies on real field data (CrUX), not lab conditions. The good-responsiveness threshold set by Google is 200 ms or less.
Why INP matters
INP replaced FID in March 2024 because it reflects perceived responsiveness across the whole session far better than a single first click. A page that is slow to react frustrates users and raises the bounce rate. As a page experience signal, a poor INP can weigh on rankings, especially between two pages with equivalent intent.
How to optimize INP
The main levers are reducing JavaScript that blocks the main thread, breaking up long tasks, deferring non-critical third-party scripts and optimizing event handlers. Reserving render space and minimizing layout recalculations also helps shorten the paint delay.
INP measures responsiveness across the entire visit, not just the first click: aim for 200 ms or less.
Frequently asked questions
FID measured only the delay of the first interaction, and only before the browser processed it. INP measures the full latency of every interaction, from the click to the visual paint. INP replaced FID as a Core Web Vital in March 2024.
An INP of 200 ms or less is considered good by Google. Between 200 and 500 ms, the page needs improvement. Above 500 ms, responsiveness is judged poor and harms the user experience.
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