First Input Delay depends on real user input, so it’s available in real user monitoring (field) tools and reports such as Chrome User Experience Report (CrUX). Calibre doesn’t report First Input Delay at this time, but Total Blocking Time (TBT) is a good synthetic monitoring alternative.
Pages with < 100 ms of input delay can be considered as fast and durations over 300 ms are considered slow.
|Good FID Measurement||Poor FID Measurement|
|≤ 100ms||> 300ms|