What is First Input Delay?

First Input Delay (FID) is another web vitals metric that considers time. It measures the time in milliseconds between the first time a user interacts with your site to when the browser reacts to that interaction.

For example, a user may press a button. The time between the visitor pressing that button and the browser taking them to the related web page is the FID.

This measurement lets search engines know about the responsiveness and interactivity of your website. If visitors have to wait around for the browser to respond, they are more likely to click off the site and never come back.

The lower your FID score, the better your website will rank:

• 2.5 seconds or less is good
• Between 2.5 and 4 seconds needs improvement
• More than 4 seconds is poor

If you need to improve your First Input Delay, you should consider reducing JavaScript execution time. You could also look at how third-party code is affecting your loading speed.