First Input Delay (FID) was the Core Web Vital measuring a page's input responsiveness — specifically, the delay between a user's first interaction (a click, tap, or keypress) and the moment the browser began processing the event handler for that interaction. FID was a Core Web Vital from May 2020 until 12 March 2024, when Google retired it and replaced it with Interaction to Next Paint (INP) as the responsiveness metric in the Core Web Vitals set.
FID is a historical metric only. Any SEO or performance recommendation still citing FID as a live Core Web Vital is working from outdated knowledge. There is no current FID score in Google Search Console's Core Web Vitals report or in Google's ranking signals — it was removed from both when INP replaced it.
The reason for the replacement was a fundamental limitation in what FID measured: it only captured the delay before event processing began, ignoring the processing and rendering work that followed. A page could pass FID's "good" threshold of 100 milliseconds while still delivering sluggish, janky interactions — because the bulk of the latency happened after the browser picked up the event. INP captures the full duration from input to next paint, giving a more accurate picture of how responsive a page actually feels. Sites that were previously optimizing for FID should redirect that effort to reducing INP.