INP: what it is and how to check your website's response speed

INP (Interaction to Next Paint) is the metric that measures how long your website takes to react when someone clicks, taps the screen or presses a key. Since 12 March 2024 it has replaced FID as one of Google’s Core Web Vitals metrics. If your website gets stuck “thinking” when opening a menu or submitting a form, INP reflects it, and it is something you can check today with free tools.

What is INP and which values are considered good?

FID only measured the first interaction. INP looks at all the interactions during the visit and reports one of the slowest. It is a more demanding measurement and closer to what a real user experiences.

According to the official web.dev documentation, the thresholds are as follows, assessed at the 75th percentile of visits:

• Good: 200 milliseconds or less.
• Needs improvement: between 200 and 500 milliseconds.
• Poor: more than 500 milliseconds.

Assessing the 75th percentile means it is not enough for your website to run well on your own computer: three out of four visits should meet the threshold, including those from modest mobile phones with a mediocre connection.

How do I check my website’s INP?

You need to distinguish between field data (real visits) and lab data (simulated tests). INP is mainly assessed with field data. A sensible order:

1. Search Console: in the Core Web Vitals report you will see which groups of URLs are red or amber on mobile and on desktop. The data is accumulated over a window of about 28 days, so changes take a while to show up.
2. PageSpeed Insights: enter a specific URL and look at the real-user data section. If your website has little traffic, there may not be enough data; that is normal.
3. Chrome DevTools: useful for reproducing a slow interaction (opening the menu, filtering a list, submitting a form) and seeing which script blocks the response.

It is worth noting the starting value and the date before touching anything. Measuring before and after is what separates a real improvement from an impression; that is what our analytics and measurement work is about.

What tends to make INP worse on SME websites?

It is almost never a single fault. These are the most common causes, in general terms:

• Accumulated third-party scripts: chat, tag manager, advertising pixels, maps, heatmaps, embedded reviews. Each one competes for the same browser thread.
• Too many plugins or add-ons in content management systems such as WordPress, with JavaScript that loads on every page even though it is only used on one.
• Poorly integrated cookie banner: if it blocks the thread on loading or on accepting, the first interaction suffers.
• Heavy menus, filters and forms that run a lot of code on every keypress or tap.
• Overloaded templates: visual builders with layers of code that nobody uses. Good web and landing page design done with performance in mind helps here.

Will improving INP make me rise in Google?

No promises: there is no guarantee that improving one metric will change your position. In its Core Web Vitals documentation, Google states that its ranking systems take these metrics into account, but also that it aims to show the most helpful content even if the page experience is not perfect. In other words: INP is one more factor, and it does not replace relevant content or a good structure.

What you can reasonably expect is a website that is more pleasant to use. A form that responds instantly and a menu that does not freeze reduce abandonment, and you can measure that in your own data, without depending on what the search engine does.

Where do I start this week?

Do not try to fix the whole website. Prioritise by impact:

1. Open Search Console and find the group of URLs with the worst INP, starting with mobile.
2. Identify the affected template (product page, blog post, contact form): fixing one template improves dozens of pages.
3. Take stock of third-party scripts and ask about each one: who uses it and what does it contribute? Remove or delay those that do not justify their cost.
4. Change one thing at a time and note the date, so you can link improvements to changes.
5. Look at the field data again after a few weeks, not a few days.

If you would rather have someone review the performance, content and technical side of your website with you using a measurable approach, tell us about your case through our online visibility page and we will tell you what to fix first.