Suggest an editImprove this articleRefine the answer for “What is FID (First Input Delay)?”. Your changes go to moderation before they’re published.Approval requiredContentWhat you’re changing🇺🇸EN🇺🇦UAPreviewTitle (EN)Short answer (EN)**FID (First Input Delay)** is a metric that measures **the delay between a user's first action and the browser's response**. **Key point:** as of March 2024, FID has officially been replaced by INP (Interaction to Next Paint), a more accurate responsiveness metric, but FID is still found in older systems and materials.Shown above the full answer for quick recall.Answer (EN)Image**FID (First Input Delay)** is a metric that measures **the delay between a user's first action and the browser's response**. ### What counts as an "action"? - clicking a button, - pressing a key, - selecting a form field. (Scrolling and zooming do not count.) ### What it looks like: The user clicks, but nothing happens. Why? Because the browser is **still busy** (for example, processing heavy JavaScript). FID shows **how quickly the interface can start responding**. ### The benchmark: - **Good:** up to 100 ms - **Acceptable:** 100-300 ms - **Poor:** more than 300 ms ### Why it matters: Even if the page has visually loaded, FID shows **whether you can actually interact with it yet**. If a user presses a button and it stays "silent", that's bad UX. --- ### Important: As of March 2024, **FID has officially been replaced by INP (Interaction to Next Paint)**, a more accurate responsiveness metric. But FID is still used in older systems and materials, so knowing it remains relevant.For the reviewerNote to the moderator (optional)Visible only to the moderator. Helps review go faster.