INP Replaces FID: What It Means for Web Performance

As of March 2024, Interaction to Next Paint (INP) will replace First Input Delay (FID) as a Core Web Vital. Find out what this means for your website’s performance, responsiveness, and Google rankings.

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First Input Delay (FID)

First Input Delay (FID) measures the time it takes for the browser to process a user’s first interaction, such as clicks, keydowns, mousedowns, and pointerdowns. In essence, FID tracks the delay between the user’s input and the browser’s response, helping to gauge responsiveness.

However, FID has its limitations. It only captures the first interaction, which doesn’t provide a full picture of the overall responsiveness of the page. This is why Google decided to replace FID with Interaction to Next Paint (INP).

What Is INP?

INP is a new metric that measures a webpage’s responsiveness by tracking the latency of all interactions during the lifespan of a user’s visit. It includes all clicks, taps, and keyboard interactions, offering a clearer representation of a site’s interactivity. After a year of testing, Google announced that INP would replace FID as part of the Core Web Vitals in March 2024.

Why Is INP Important?

Chrome usage data shows that 90% of a page’s time is spent after it loads. This means that the ability to measure responsiveness throughout the page’s lifecycle is crucial. INP does just that by monitoring the time taken for visual feedback to occur after every interaction, helping developers identify areas of improvement for better user experiences.

INP Replacing FID

What Does This Change Mean for Google Search Console?

Starting in March 2024, INP will become the new responsiveness metric in Google Search Console, replacing FID. The Core Web Vitals report will highlight INP performance, helping site owners and developers understand how responsive their sites are in real-world scenarios. This change ensures that every user, regardless of device or connection, receives the best possible experience.

How to Measure and Improve INP

You can measure INP using both field and lab tools:

  • Field Tools: PageSpeed Insights, CrUX API, web-vitals JavaScript library.
  • Lab Tools: Lighthouse in DevTools, Lighthouse npm module, and the Web Vitals extension for Chrome.

To improve INP:

  • Reduce the number of JavaScript files on your page.
  • Optimize your images and videos.
  • Use a CDN to serve your static content.
  • Minify and gzip your HTML, CSS, and JavaScript files.
  • Avoid using heavy plugins and extensions.

What Is Considered Good INP?

INP scores are classified into three categories:

  • Good: INP below or at 200 milliseconds indicates good responsiveness.
  • Needs Improvement: INP above 200 milliseconds and below or at 500 milliseconds.
  • Poor: INP above 500 milliseconds signifies poor responsiveness.

A low INP indicates that a page is consistently responsive to user input, contributing to a better user experience.

Next Steps for Site Owners and Developers

Site owners and developers should begin testing and optimizing for INP ahead of its implementation as a Core Web Vital metric. Follow best practices, utilize Google’s tools and resources, and continue monitoring your site’s responsiveness to maintain good performance and provide a superior user experience.