How is INP different from FID, and why is it preferred?
How is INP different from FID, and why is it preferred?
Ask by Anubhav Sharma
Updated 05 May 2025
INP (Interaction to Next Paint) and FID (First Input Delay) are both important for understanding how interactive a website is, but they measure different things and show different aspects of user experience.
FID (First Input Delay)
- What it measures: This shows the time between when a user first interacts with the page, like clicking a button, and when the browser starts to process that action.
- Limitation: FID only looks at the first interaction and doesn't account for how long it really takes to process the action or how the page visually responds, so it doesn’t give the full picture.
INP (Interaction to Next Paint)
- What it measures: INP tracks how long it takes for all interactions—like clicks, taps, or key presses—during a user’s visit and reports the slowest interaction. It looks at the whole process from input to when the visual update happens, giving a better sense of how responsive the site is.
- Visual feedback included: INP measures the time until the screen updates, which means it covers more than just the initial delay.
Why INP is Better than FID
- Wider Measurement: INP shows the quality of interactions throughout the entire session, rather than just the first one.
- Better Insight Into User Experience: It reflects what users really feel, like how long it takes to see a reaction on their screens.
- Future-Proof Metric: INP fits better with how users see performance, making it a more trustworthy way to measure how responsive a page is.