Replacing FID, Core Web Vitals Bring INP to Search Console

Core Web Vitals has announced a new indicator in its report, namely INP (Interaction to Next Paint), replacing FID (First Input Delay). Google broadcasted this modification in January and has included INP in Google Search Console as a first-class element since last June.

What Is INP? 

INP, or Interaction to Next Paint, is a metric that evaluates the overall response of a page to user interactions, such as clicks, taps, and keyboard inputs. This indicator is capable of observing the time it takes for a page to respond to interactions occurring throughout a user's visit.

The final INP value is the longest interaction observed without including outliers (data points significantly different from others). If the INP value is low, it means the page can respond to most user interactions quickly and consistently.

Then, what constitutes a good page response? A good response can be assessed by how quickly a page takes action. When a page responds to an interaction, the browser provides visual feedback rendered in the next frame, indicating that the interaction was successful.

The goal of this metric is to minimize the time from when a user starts interacting with a page until the next frame painting. 

What Are the Differences between INP and FID? 

As mentioned earlier, INP has now replaced FID in Core Web Vital reporting. However, what sets these two metrics apart?

Both INP and FID are indicators that assess how responsive a page is to user interactions. However, FID only measures the delay of the first input interaction on a page. 

On the other hand, INP enhances the measurement from FID by considering interactions across all pages from the beginning of input delay, the time required to execute event handlers, to when the browser performs frame painting.

Thus, it can be concluded that INP and FID assess different levels of responsiveness. FID measures responsiveness to evaluate a page's initial impression on users, while INP evaluates overall responsiveness regardless of when interactions occur.