First Input Delay (FID) – Defined, Measured and How to Fix

First Input Latency (FID) is the time from when a user first interacts with your page to when the page responds. It measures responsiveness and is one of the three Core Web Vitals metrics Google uses to measure page experience.

Examples of interactions include:

• Click on a link or button.
• Enter text in an empty field.
• Select a drop-down list.
• Click on a checkbox.

Some events such as scrolling or zooming are not counted.

Let’s see how fast your FID should be and how to improve it.

A good FID value is less than 100 ms and should be based on Chrome User Experience Report (CrUX) data. This is data from real users of Chrome who are on your site and have agreed to share this information. You need 75% of interactions to respond in less than 100ms.

Your page can be classified into one of the following buckets:

• Good: <=100 ms
• Needs improvement: >100 ms and <=300 ms
• Weak: >300 ms

FID data

95.3% of the sites are in the good FID bucket as of April 2023. This is an average across the site. As we mentioned, you need 75% of interactions to respond in less than 100ms to show this well here.

The majority of pages on most sites pass the CWV check for FID. I don’t believe this is really the best method to measure responsiveness, and Google will replace FID with Interaction to Next Paint (INP) in March 2024. Instead of just looking at the first input, INP looks at the latency of all the interactions a user makes.

When we a study on Core Web...