Measurement
FID (First Input Delay)
First Input Delay (FID) is a Core Web Vitals metric that measures the time from when a user first interacts with a page (clicks a button, taps a link) to when the browser is able to start processing that interaction. A good FID score is under 100 milliseconds. FID was replaced by Interaction to Next Paint (INP) in March 2024 as an official Core Web Vital.
FID is measured using real-user monitoring (RUM) data from the Chrome User Experience Report (CrUX), accessible in Google Search Console's Core Web Vitals report and PageSpeed Insights. Lab-based tools like Lighthouse approximate interactivity through Total Blocking Time (TBT) as FID requires real user interaction.
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Related Terms
Measurement
DCL (DOM Content Loaded)
Refers to the time frame from entering a web page to the loading of the content.
Measurement
FCP (First Contentful Paint)
Refers to the point at which the first pixel renders on a screen after a user navigates to a web page.
Measurement
FMP (First Meaningful Paint)
The metric representing the time it takes for a page's primary content to appear on the screen.
Measurement
TTFB (Time to First Byte)
Refers to the time between the browser requesting a page and when it receives the first byte of information from the server.