A Complete Guide for Interaction to Next Paint (INP) - The New Core Web Vital

A Complete Guide for Interaction to Next Paint (INP) - The New Core Web Vital

July 31, 2023
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Interaction to Next Paint (INP): The New Responsiveness Metric

Every website owner wants their webpage to be on Google's top ranking. However, attaining this position is no easy job. For years, people have tried to perfect the art of accurate SEOs and quality content to ensure that their web pages rank at the top.

Some even tried unveiling Google's secret rankings method, but the Search Engine always kept a tight lip. Well, until recently, when Google gave an insight into how it judges page ranking.

So, if you are a website owner who wants to rank on top, you might need to keep some of Google's tricks in mind. Other than this, the use of INP might work wonders for you. Don't know what it is, then hop on below.

What is Interaction to Next Paint (INP)?

Interaction to Next Paint – or INP- is an experimental field metric that Google has produced to measure the load responsiveness on your website.

Recently when Google gave users an insight on what factors they consider when assessing which websites should make it to the top of the search engines, the tech giant issued a number of core web vitals.

The three main core vitals were:

1.   Loading

2.   Interactivity (FID)

3.   Visual Stability

While the other two factors are just as crucial, interaction is one key point that any visitor to your website focuses on. So, what is interaction?

Users who visit a website expect their actions to be quickly changed into results. This means when one user clicks on a particular page on the website to open; they require the results rapidly. Lagging in the results for users can discourage them from using the website and back off.

The User Behavior Count as an INP interaction

As mentioned, the interaction happens when users click to perform a particular task to the point they obtain the results. How many times has it happened to you that when searching through a website, any lagging caused you to back out and search for a faster one? Many, right? Well, this is the case for everyone.

Based on their analytics and some industry research, Google stated that users are easily discouraged from staying on websites that fail to show the results within 2.5 seconds or 200 milliseconds or less. That is precisely what INP helps to calculate.

Considering how INP measures the interactivity time between the two points – which are the user effort to initiate a task to the point they receive the results, it can easily be assessed that INP interaction based on user behaviours plays a significant role in keeping your website among the top ranking.

As far as INP goes, only the following interaction types are observed (same with FID):

  • Clicking with a mouse.
  • Tapping on a device with a touchscreen.
  • Pressing a key on either a physical or onscreen keyboard.

Interactions may consist of two parts, each with multiple events. For example, a keystroke consists of the keydown, keypress, and keyup events. Tap interactions contain pointerup and pointerdown events. The event with the longest duration within the interaction is chosen as the interaction's latency.

What's a pointerup event:

For mouse, this is when the device transitions from at least one button depressed to no buttons depressed. For touch, this is when physical contact is removed from the digitizer. For pen, this is when the pen is removed from the physical contact with the digitizer while no button is depressed, or transitions from at least one button depressed to no buttons depressed while hovering. Vice versa for pointerdown event.

Pointer Up/Down Event in real action | DEANLONG.io
Pointer Up/Down Event in real action

What's a keyup event:

The keydown and keyup events provide a code indicating which key is pressed, while keypress indicates which character was entered. However, the keypress event is depreciated.

A demonstration of key up/down events | DEANLONG.io
A demonstration of key up/down events

How Does Interaction to Next Paint (INP) Work?

INP is calculated when the user leaves the page, resulting in a single value that is representative of the page's overall responsiveness throughout the entire page's lifecycle. A low INP means that a page is reliably responsive to user input.

Now that we've made clear that INP interaction is one of the core values which might help your website stay among the top rankings, it is essential to understand how it works. 

Another reason why understating and knowing how INP works is that there are high chances that Google might add INP along with its already existing FID (First Input Delay) to measure the interactivity of a website or completely replace the FID with the newer version of INP. So, to understand this interaction, read below.

Interaction latency is the single longest time or duration of an event, specifically the part of that particular interaction. Hence, the interaction latency is measured from the user's first interaction with the page to the point when the desired results have been achieved once all handlers have executed the requirements. This process is broken down into three main interaction pathways:

  • Input Delay – users interact with the website's page while the event handlers deliver
  • Processing Time – the total time it will take for the code to be executed in associated event handlers.
  • Presentation Delay – when the handlers have finished executing and the desired page is loaded.

The quicker these three pathways will be covered, the faster the user desired results will be obtained, ultimately improving your page's interaction, and bringing it to the top of the search engine.

First Input Delay and Interaction To The Next Paint | DEANLONG.io
First Input Delay and Interaction To The Next Paint | Source: Web.dev

How is INP Different from First Input Delay (FID)?

Checklist for Video Mobile Design
Difference FID INP
Full Name First Input Delay Interaction To The Next Paint
Definition The time from when a user first interacts with a page (i.e. when they click a link, tap on a button, or use a custom, JavaScript-powered control) to the time when the browser is actually able to begin processing event handlers in response to that interaction. Represent a page's overall responsiveness by measuring all click, tap, and keyboard interactions made with a page. The longest of those observed interactions—with some exceptions noted below—is chosen as the page's INP value when the user is done with the page.
Purpose Measuring load responsiveness: how quickly a page can load and execute any required JavaScript code in order for components to respond quickly to user interaction Measuring the latency of every tap, click, or keyboard interaction made with the page
Calculation The FID value you care most about on desktop should be the 95th–99th percentile of desktop users, and the FID value you care about most on mobile should be the 95th–99th percentile of mobile users. For pages with few interactions, the interaction with the worst latency (the 100th percentile) is chosen. For pages with many interactions, the 99th or 98th percentile is chosen.
Good Threshold <100ms <200ms
Main Difference FID only measures the "delay" in event processing. It does not measure the event processing time itself nor the time it takes the browser to update the UI after running event handlers. INP considers all page interactions.By sampling all interactions, responsiveness can be assessed comprehensively, making INP a more reliable indicator of overall responsiveness than FID.
Why The user's first impression of your site's responsiveness INP is more than about first impressions. It's an overall page interactive experience
Field Tools

You must have read above that there are chances that Google might replace FID and bring INP entirely into the picture as the new core web vital. So, what is the reason behind this? And what makes FID different from INP?

Well, to begin with, FID has been in the picture for a long time, and its replacement with something better was inevitable. With INP, website owners and Google will benefit on a larger scale. Why so?

While FID takes into account only the first interaction with the website or page, INP, in comparison, measures all interactions during the session. Other than this, while FID is capable of calculating only the input delay, the results that INP shows include input delay, time taken by event handlers to perform and execute and the time it takes for the next frame to load.

Moreover, the results INP gives is in respect to the overall page responsiveness. This is because the calculated result is determined when the users leave the page after performing all tasks or opening all pages. In comparison, FID, as mentioned, only takes the input of the first interaction on the page and concludes the results based on it.

So, when INP concludes results, it is based on the summary of all actions through the session, while FID only concludes results based on the first interaction. Therefore INP is not only different from FID but is considered better and more efficient.

FID example and how is it measured
FID example and how is it measured | Source: Web.dev
Identify the key difference between FID & INP - you can tell how different they are in this picture
Identify the key difference between FID & INP - you can tell how different they are in this picture | Source: Web.dev

How Can One Measure INP?

With it now clear that INP is the new core web vital metric in line, and its measurement plays a crucial role in assessing your position, shouldn't you be focusing on learning how to measure INP too?

The best part about INP is that it gives website owners the freedom to assess how quick the response and interaction on their website is and shows them ways to improve it too. So, if you run a website, here are ways you can measure your INP easily.

INP can be measured in:

  1. Field
  2. Lab

In Field assessment, the following tools can be used:

For Lab assessment, the following tools are used:

Measure INP Through JavaScript

In order to measure your INP through JavaScript, use the web-vitals JavaScript Library. The Library will export an "onINP" Function for you. To obtain the INP data, you must gain access to version 3 of web vitals.

Version 3 is currently in beta version, and to access it, you have to use the following command:

  • npm install web-vitals@next –save
npm install web-vitals@next –save

You can then get a page's INP by passing a function to the onINP method:

import {onINP} from 'web-vitals';onINP(({value}) => {  // Log the value to the console, or send it to your analytics provider.  console.log(value);}); 

Through this, you can easily measure the INP and figure out what changes towards betterment you need to make.

With this out of the way, suppose your interaction score claimed that your website is lacking in some aspect, so what do you do? The INP is a complicated metric. This is because it concludes the results based on all interaction that happens within a single user's session. So, even if all other interactions or results were great, but one task lagged, the INP score will drastically decrease.

However, this isn't worth worrying about because you can always improve the interaction with the Interaction to Next Paint.

What are the Good and Bad Values of the Interaction to Next Paint (INP)?

The Interaction to Next Paint is a pretty strict judge of character. The new core web vital metric requires your website to have the 75th percentile of page load recorded in the field to stay below 200 milliseconds. 

The millisecond value your website acquires is divided into three different categories, each of which tells the website user how well their website is doing in terms of interaction.

What are the Good and Bad Values of the Interaction to Next Paint | DEANLONG.io
What are the Good and Bad Values of the Interaction to Next Paint

  • Any INP at 200 milliseconds or below indicates that the website has good responsiveness.
  • An INP between 200-500 milliseconds indicates that the website is moderate and could do well with some improvement.
  • Meanwhile, any INP above 500 milliseconds is a major indicator that the website has poor responsiveness, which can ultimately affect its position on the search engine.

So, if you run a website, the above scoring categories can quickly help you assess what position of responsiveness your website stands. If by chance, the scoring is low, you can always check out ways to improve them online. 


People have tried different ways to ensure that their website ranks on top. However, while proper SEO wordings on articles play wonders, the new core web vital metric – INP, is about to change the entire game.

So, focus on learning how to measure INP, consider it every time, and we hope your websites will be making their way to the top soon. If you were confused about what INP is and how it works, we hope this article clears everything up for you.


  1. https://www.corewebvitals.io/pagespeed/interaction-to-next-paint
  2. https://www.iron-out.io/blog/what-is-interaction-to-next-paint-inp-and-how-to-measure-it#:~:text=The%20Interaction%20to%20Next%20Paint,page%20will%20display%20visual%20feedback.
  3. https://web.dev/inp/
  4. https://web.dev/fid/


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Dean Long | Expert in Growth MarketingHongxin(Dean) Long

Dean Long is a Sydney-based performance marketing and communication professional with expertise in paid search, paid social, affiliate, and digital advertising. He holds a Bachelor's degree in Information Systems and Management and is also a distinguished MBA graduate from Western Sydney University.

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