First Input Delay (FID)
A deprecated Core Web Vital that measured the delay before the browser could respond to the first user interaction.
Quick Definition
A deprecated Core Web Vital that measured the delay before the browser could respond to the first user interaction.
Full Explanation
First Input Delay (FID) was one of the original Core Web Vitals, measuring the time from when a user first interacts with your page (clicking a link, tapping a button) to when the browser can begin processing that interaction. FID was replaced by Interaction to Next Paint (INP) in March 2024 because FID only measured input delay for the first interaction and didn't capture processing time. While FID is no longer a Core Web Vital, it's still reported in some tools. A good FID was under 100ms. If you see FID in your reports, focus on INP instead as it's the current ranking factor.
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Related Terms
Interaction to Next Paint
A Core Web Vital that measures page responsiveness by tracking the latency of user interactions.
Total Blocking Time
A lab metric measuring the total time the main thread was blocked long enough to prevent input responsiveness.
Core Web Vitals
A set of three metrics (LCP, INP, CLS) that Google uses to measure user experience and as ranking factors.