# FID (First Input Delay)

> Measures the time from first user interaction to browser response.

Source: https://anotherseoguru.com/en/glossary/fid

First Input Delay (FID) measures the time between when a user first interacts with your page (clicks, taps, presses a key) and when the browser can respond. It indicates how responsive your page feels.

## Example

Good: <100ms, Needs Improvement: 100-300ms, Poor: >300ms. If you click a button and nothing happens for 500ms, that's poor FID.

## How to apply it

Minimize JavaScript execution, break up long tasks, use web workers, defer non-critical JavaScript, remove unused code, reduce third-party script impact.

> **Pro tip:** FID is being replaced by INP (Interaction to Next Paint). Start measuring INP now as it will become the primary responsiveness metric.

## Related terms

- [INP (Interaction to Next Paint)](https://anotherseoguru.com/en/glossary/inp)