First Input Delay (often referred to simply as FID) is a Core Web Vitals measure of the time it takes for a user to begin interacting with a page to the time that the browser begins processing that interaction. For instance, if a user clicks on a “magnify” button on an image, the time between that click and the browser beginning to process that click is the FID.
Of course, websites and webpages are motivated to reduce their FID metrics to as low as possible in order to make their pages more responsive. There are three levels for the FID on webpages, which are:
Good: 0 to 100 milliseconds
Needs Improvement: between 100 and 300 milliseconds
Poor: 300 milliseconds or longer
Our Core Web Vitals Checker can determine what your FID score is.
