<b>Why INP replaced the old FID metric</b>

<b>Why INP replaced the old FID metric</b>

INP — Interaction to Next Paint — measures how quickly your page visibly reacts when someone taps a button or types. It replaced an older metric called FID (First Input Delay) in March 2024.

The difference matters: FID only timed the <i>very first</i> click, and only the waiting part, not the response. INP watches <i>every</i> interaction across the whole visit and reports one of your worst. Think of FID as judging a waiter by how fast they greeted you — INP judges the whole meal.

What this means for you:
— A page could pass FID but fail INP, because problems show up later
— A slow dropdown, a laggy 'add to cart', a janky filter — all count now
— Good INP is 200 milliseconds or less

<b>Try this:</b> Click around your own site like an impatient user. Anything that feels sticky is your INP suspect.