FID (First Input Delay) was a Core Web Vital that measured responsiveness by tracking the delay between a user's first interaction (click, tap, or key press) and the browser's response. Google replaced FID with INP () on March 12, 2024.
How FID Worked
FID measured only the input delay portion of event processing. When a user clicked a button, FID captured the time between the click event and when the browser could begin processing the event handler. It did not include the time to run the handler or update the display.
The metric focused exclusively on the first interaction because initial responsiveness shapes user perception of page quality.
FID Thresholds (Historical)
Before deprecation, these thresholds applied:
- Good: Under 100 milliseconds
- Needs Improvement: Between 100 and 300 milliseconds
- Poor: Over 300 milliseconds
To pass assessment, at least 75% of page visits needed FID under 100ms.
Why FID Was Replaced
FID had limitations that INP addresses. FID only measured the first interaction, ignoring subsequent interactions that might be slower. It also excluded event processing and rendering time, giving an incomplete picture of responsiveness.
INP tracks all interactions throughout the page lifecycle and measures the full duration from input to the next visual update. This provides a more accurate representation of real user experience.
Migration Timeline
FID support officially ended on September 9, 2024. Google Search Console removed FID reporting when INP became a Core Web Vital. PageSpeed Insights and Chrome User Experience Report maintained FID data for six months to help developers transition their monitoring.
