What happened to First Input Delay (FID)?

First Input Delay (FID) was retired as a Core Web Vital in March 2024 and replaced by Interaction to Next Paint (INP). If an old guide tells you to optimise for FID, it is outdated:

• FID only measured the first interaction — and only the delay before processing started, which made it easy to pass while the site still felt sluggish.
• INP measures every interaction — and the full time until the screen visibly responds, so it reflects real responsiveness far better.
• The threshold changed too — INP’s “good” bar is under 200 milliseconds at the 75th percentile.

Nothing you need to do is lost — the work that helped FID (less blocking JavaScript) helps INP too, just held to a tougher standard. Stop optimising for FID; the metric Google now scores is INP.