FID Checker – First Input Delay

Measure First Input Delay (FID) and analyze how quickly your website responds to user interactions. Part of Core Web Vitals and essential for performance optimization.



What Is First Input Delay (FID)?

FID measures the time between a user's first interaction (click, tap, or key press) and when the browser responds to that interaction.

A low FID means your website is responsive and provides a better user experience.

FID vs INP (Core Web Vitals Update)

FID has been replaced by INP (Interaction to Next Paint) as part of Core Web Vitals. INP provides a more complete measure of responsiveness across all interactions.

However, FID is still useful for understanding input delay and optimizing performance.

How to Improve FID

Frequently Asked Questions

What is FID?

It measures the delay between user interaction and browser response.

Is FID still relevant?

It has been replaced by INP but is still useful for analysis.

How can I improve FID?

Optimize JavaScript and reduce blocking tasks.