Changes are on the horizon for Google’s Core Web Vitals (CWVs). For years, web developers have been monitoring their scores for Largest Contentful Paint (LCP), First Input Delay (FID), and Cumulative Layout Shift (CLS). However, starting in March of 2024, Interaction to Next Paint (INP) will be replacing FID as one of these core metrics.
While INP has been in testing since 2022, it is no longer considered experimental, and is ready for measurement on many of the most popular web development tools. Let’s dive into a few key notes about the future of Interaction to Next Paint and how it will affect your ability to measure a website’s technical performance.
What is Interaction to Next Paint?
Like the other CWVs, the INP score measures a specific facet of the user experience on any particular web page. In the case of Interaction to Next Paint, you’ll be able to measure the responsiveness of the user interactions on a webpage. Usually measured in milliseconds, a page’s INP will inform web developers about the maximum amount of latency that a user might experience while interacting with a web page.
Why is FID Being Removed?
In 2022, before revealing INP, Google highlighted a few of the limitations and opportunities to improve FID. Plans to rework this metric were centered around FID’s inability to give an accurate picture of the website’s interactivity and the user experience after the first click. While FID is a good starting point, its respective score didn’t inform developers about the scores of other interactions that might also occur. Rather than adjusting the fundamentals of FID, Google decided to create INP to more or less replace FID as one of the CWVs.
What’s the Difference Between INP and FID?
Both FID and INP measure the interactivity of a page, but with slightly different data points. When a user visits your website and clicks on a link to another page, FID measures the duration between the user’s button click and the browser’s response to that event (for example, loading another page). INP measures the delay for all of the interactions on a page and reports the slowest load time. To developers, this highlights the “worst-case scenario” when loading an asset on a page.
Another major difference between these two metrics is the timeframe measured when an interaction occurs. FID measures how long it takes for the browser to start loading the next visual after someone clicks or presses a key. On the other hand, when users interact with the same web element, INP measures how long it takes for the resulting visual to completely finish loading. This is usually a more meaningful metric, as it better illustrates how long it takes for users to actually start viewing the new page, rather than when the browser is ready to start loading it.
To summarize, when FID is measured, it only accounts for the first user interaction on a page and when the browser starts to load the resulting page/visuals. INP improves on this by accounting for all of the page interactions and reporting the longest time that it takes the browser to finish loading a result.
Where Can I View My INP Score?
Even though it isn’t a CWV yet, INP is already a visible metric on many of the most popular web development tools, like Google Search Console, the Web Vitals Chrome extension and PageSpeed Insights. INP has been in testing for over a year and is considered a reliable metric, so you’re in the clear to measure and report on your INP score.
Even though Google has confirmed that FID will be replaced by INP in March of 2024, they have not yet confirmed whether or not FID will still be visible.
What is a Good INP Score?
If your INP is 200 milliseconds or less, then your page meets Google’s requirements. When INPs are 500ms or higher, it means that your page isn’t very responsive, and you may start to notice a higher bounce rate. In addition, when INP becomes a CWV, meeting Google’s benchmark for positive INP performance will become a requirement for receiving the CWV rankings boost.
How to Improve Your INP Score
If you’re noticing an INP score 200ms or more, you may want to work with your web developers to try and increase website responsiveness. If your website is operating with a lot of tasks in the background or if your site is simply struggling to load complex graphics, you’ll suffer a higher INP time. Review the slowest interactions that are taking place on the page and consider having them removed (if irrelevant) or working alongside your developers to improve the total interaction latency of these elements.
While INP shares a lot of similarities with FID, the switch between these CWVs is a step in the right direction for measuring website interactivity and responsiveness. You can look forward to the switch in March of 2024. Until then, familiarize yourself with INP to get a head start.
