What Is Interaction to Next Paint
How INP Measures Responsiveness
Interaction to Next Paint (INP) measures how quickly a page responds to user interactions such as clicks, taps and key presses. It records the time from the interaction until the browser paints the next visual update that reflects it. A page with low INP feels responsive; one with high INP seems to ignore the visitor for a moment.
INP looks at the whole visit rather than only the first interaction. For most pages, it reports one of the slowest interactions observed, so a single sluggish menu or form field can affect the score. On pages with many interactions, a small number of the slowest ones are set aside so that one outlier does not decide the result.
Input Delay, Processing Time and Presentation Delay
Each interaction breaks into three parts:
- Input delay, the time the browser waits before it starts handling the event, often because it is busy with other work.
- Processing time, the time the event handlers take to run, such as code that updates the page after a click.
- Presentation delay, the time between finishing that work and painting the next frame that shows the result.
Any of the three can make a page feel slow. A long task from a script can cause input delay, heavy event handlers add processing time, and a large layout update can extend presentation delay.
Why INP Replaced First Input Delay
Before 2024, Google's responsiveness metric was First Input Delay (FID). It measured only the delay before the browser began handling the first interaction. FID ignored processing time and every interaction after the first, so pages with heavy handlers could score well while still feeling sluggish. INP covers the responsiveness of the whole visit, and it replaced FID as a Core Web Vital in 2024.
A good INP is 200 milliseconds or less, and above 500 milliseconds is poor. Like the other Core Web Vitals, INP is assessed from field data at the 75th percentile, so most interactions for most visitors need to be quick. The wider context is in the Core Web Vitals topic.
Frequently asked questions
What is a good INP score?
An INP of 200 milliseconds or less is good. Values between 200 and 500 milliseconds need improvement, and anything above 500 milliseconds is poor. These thresholds apply at the 75th percentile of page views, so the responsiveness must hold for most visitors, not only for those on fast devices.
How is INP different from Total Blocking Time?
Total Blocking Time is a lab metric that adds up long tasks between the first paint and the point the page becomes interactive. INP is a field metric that measures the actual interactions of real visitors across the visit. Lab tests cannot record real clicks, so Total Blocking Time is used as a stand-in.