The metric that may replace First Input Delay in Core Web Vital reports
Google introduced a new metric for page experience called Interaction to Next Paint (INP). INP is an experimental field metric that measures responsiveness. Responsiveness is how fast a page responds to user inputs and is thus a critical metric for tracking user experience scores.
Google puts a lot of emphasis on improving user experience.
The Core Web Vitals update rolled out last year is proof that user experience is a key ranking factor for Google. There is a lot of chatter about if and when INP will replace FID (First Input Delay) to become a Core Web Vitals tracking metric.
While the replacement is still not finalized, let us look at and understand this new metric and learn how we can improve our website’s performance score for INP.
Interaction to Next Paint (INP) is a field metric that measures page responsiveness. A page is considered responsive if it responds to user input quickly.
Google Webmasters blog post on page responsiveness mentions that INP is an experimental metric and will be available in Google Search Console (GSC) as “Page Experience” under the “Site Performance” section. However, currently, GSC shows FID (First Input Delay) under Site Performance instead of INP. So there is no way to get this data right now via GSC.
It is, however, currently live when checking a page’s score through Google’s PageSpeed Insights tool. Upon testing various URLs across different websites, the INP score can vary dramatically from the more traditional FID score. In cases where a website may be well-optimized towards FID and report a “good” score for this metric, the INP metric may be vastly different and unveil some additional implementations needed before scoring well there.
It can be used to measure the responsiveness of your homepage and any page on your website, especially pages that could have a lot of interactivity.
It is not supported by any third-party service right now. So if you want to use it, you will have to implement it yourself.
It depends on the Google Chrome browser, so if you want to get this data for your website, you will have to use Google Chrome as your primary browser (if you don’t already).
As mentioned above, there is no way to get this data site-wide via GSC due to FID (First Input Delay). Websites will have to check for this through the PageSpeed Insights tool manually. Hopefully, Google will begin to include INP in GSC soon or at least provide some way for webmasters and SEOs to access this data through GSC/Search Console API shortly so they can start measuring their websites’ responsiveness using this metric from a broader view, especially once this officially becomes an official Core Web Vitals metric.
INP is measured in milliseconds, and it measures the time taken for a page to respond to the first input after a user action, like clicking a link or button.
According to Google, an INP below or equal to 200 milliseconds indicates good responsiveness. An INP above 200 milliseconds and below or at 500 milliseconds means that your page's responsiveness needs improvement. An INP above 500 milliseconds implies that your page has poor responsiveness.
Yes, INP will eventually replace FID as the Core Web Vitals metric. Google representatives pointed out that FID has some reasonably big blind spots. For example, First Input Delay (FID) only accounts for the first interaction. Moreover, it only measures input delay, not the processing time of event handlers or the delay in displaying the next frame. In contrast, INP considers all page interactions.
Given that FID is also a load responsiveness metric, its rationale is that if the first interaction made with a page in the loading phase has little to no perceptible input delay, the page has made a good first impression.
INP goes beyond first impressions. From the moment the page begins loading until the moment the user leaves, INP tracks the entire range of interactions that may occur.
This approach provides a comprehensive look at responsiveness and makes INP a more reliable indicator of responsiveness than FID.
It's best to think of INP as similar to Cumulative Layout Shift (CLS). It is a full-cycle metric that continually changes and updates throughout the entire lifecycle of the page. Like CLS, you do not want to record an INP value before the user leaves the page.
Since INP is a new metric, webmasters and SEOs have to learn how to interpret this data. It will take a while for the industry to agree on an acceptable level of INP. Therefore, you must start measuring your website’s INP now and keep measuring it until the industry has some agreed-upon thresholds.
Keep in mind that Google doesn't expect you to reach zero or even near-zero values to get a good score. It is more important that the trend is positive and your website's performance is improving over time.
Here are some tips from Google to improve INP :
Identify all user interactions on your page (e.g., clicks, scrolls, form submissions, etc.) and measure the input delay for each one (see the section below for details).
Measure the input delay for each interaction on many different devices (desktop/laptop, phone, tablet).
Measure over multiple days (preferably at least 5 days per week) using different devices and internet connections (e.g., home WiFi/cellular).
As soon as you obtain reliable data, work with your engineers/developers to improve input delay by optimizing event handlers or resolving network issues.
If you don't have access to engineers/developers who can help optimize your code or resolve network issues, try using AMP, which has been built from the ground up with performance in mind.
Measure again after making changes and iterate until your input delay is consistently fast.
If you use Google Analytics, here is a guide on measuring input delay in GA.
It is highly recommended to measure the INP metric for your website because it is crucial for user experience and SEO. You can use it to evaluate your website against competitors and see how much time you need to decrease before you can claim that your website is “responsiveness optimized.”
It will help improve your SEO once it officially becomes a Core Web Vitals metric, but it is also just an excellent best-practice UX tactic that can improve other KPIs such as conversion rates.
Suppose you don’t have the resources or time to optimize your website right now. In that case, we suggest starting with the low-hanging fruits like lazy loading of images and videos, pre-caching content, and optimizing the critical rendering path (doing these steps will make a huge difference in responsiveness).
INP is one of the metrics to track page experience for users. Therefore, your website must be optimized for all the Core Web Vitals metrics to improve SERP rankings. Read our Core Web Vitals Guide to improve and automate your page experience optimization efforts.