How to reduce INP in WordPress and improve Core Web Vitals

There are websites that load quickly, but when you click a button, open a menu, or try to submit a form… they simply don’t respond. For a fraction of a second, it seems like nothing is happening, until they finally react.

That feeling of slowness is precisely what the Interaction to Next Paint (INP) measures, one of the metrics that are part of Google’s Core Web Vitals.

If you manage a WordPress site, improving this metric not only helps provide a smoother experience for your visitors. It can also contribute to a better perception of quality, reduce frustration during navigation, and be part of a global performance optimization strategy.

In this guide, we will see what INP is, why it can be affected in WordPress, and how to reduce it step by step by reviewing the frontend, plugins, third-party scripts, and the infrastructure on which your website operates.

What is INP and why does it matter in WordPress?

The Interaction to Next Paint (INP) is a metric that measures how long it takes for a page to visually respond after a user interacts with it.

This interaction can be a click on a button, a tap on the screen, opening a menu, submitting a form, or even a keystroke.

In other words, INP does not measure how long it takes for a page to load, but how long it takes to react when the user expects a response.

This difference is important.

A website can display all its content in just two seconds and yet offer a poor experience if each click takes half a second to execute.

Imagine an online store where the «Add to cart» button does not respond immediately. Although the product ends up being added correctly, that small delay creates uncertainty. Many users click the button again thinking it didn’t work, causing duplicate actions or abandoning the purchase out of frustration.

INP tries to reflect precisely that real user perception.

That’s why Google replaced the old First Input Delay (FID) with this new metric. While FID only analyzed the first interaction, INP evaluates the responsiveness throughout the entire visit, offering a much more representative picture of how a page actually behaves.

In WordPress, this metric is often affected by factors such as:

• Excessive JavaScript.
• Plugins that load unnecessary scripts.
• Overly heavy visual builders.
• Third-party widgets and tools.
• Long tasks that block the browser.

The good news is that most of these problems can be identified and corrected with an appropriate front-end optimization strategy.

What INP values are considered good?

Google establishes three ranges to interpret INP.

It’s not about an absolute pass or fail, but a reference that helps identify if a page responds quickly enough to user actions.

It’s important to note that these values are not the same for all pages.

A simple landing page with just a few interactive elements usually achieves better results than an admin panel, a product configurator, or a web application where many actions are executed via JavaScript.

It’s also important to distinguish between lab data and real data.

Audit tools can simulate the behavior of a page under certain conditions, but Google also collects anonymous information from real users through the Chrome User Experience Report.

That’s why it’s possible to get a good result in Lighthouse and still detect issues in Google Search Console. Simulations help find improvement opportunities, but real data reflects how your visitors actually experience your website.

Why WordPress can have INP problems?

WordPress doesn’t have a bad INP by definition.

In fact, a well-optimized installation can offer an excellent experience even in complex projects.

The problem arises when layers of functionality accumulate, forcing the browser to do too much work before responding to an interaction.

In many cases, it’s not a single element responsible, but the sum of small factors that, together, end up slowing down the page.

Excessive JavaScript

JavaScript is the main driver of interactivity on a modern web.

Thanks to it, dropdown menus, filters, dynamic forms, sliders, instant search engines, or shopping carts work.

However, the more JavaScript code the browser has to execute, the more time it remains busy and the less capacity it has to respond immediately to user actions.

It’s common to find multipurpose themes or visual builders that load hundreds of kilobytes of JavaScript, even if the page only displays text and an image.

Each of these files needs to be downloaded, parsed, and executed before certain functions are available.

The result is a browser with more work than necessary and a poorer response capacity.

Plugins that load scripts site-wide

Not all plugins affect performance in the same way.

Many add JavaScript and CSS files on absolutely every page, even if that functionality is only used on one of them.

A very common example is contact forms.

If you only have a form on the contact page, it doesn’t make sense to load all its scripts also on the blog, the homepage, or product pages.

The same goes for:

• Advanced forms.
• Online chats.
• Sliders.
• Pop-ups.
• Analytics tools.
• Marketing widgets.

Each additional resource increases the browser’s workload and can worsen the page’s response capacity.

Third-party scripts

Not all JavaScript loaded by a website comes from WordPress.

In fact, in many projects, the greatest impact on INP comes from external tools we add over time.

It’s common to find pages that simultaneously load:

• Google Tag Manager.
• Google Analytics.
• Meta Pixel.
• Chat widgets.
• Interactive maps.
• Embedded videos.
• Social media sharing buttons.
• A/B testing tools.
• Personalization platforms.

Each of these services incorporates its own scripts, competing for the browser’s execution time.

The problem usually doesn’t appear when we install just one, but when they accumulate. Over time, many websites end up running dozens of third-party scripts without anyone questioning if they are still really necessary.

A very common case is a company that installs a chat for customer service. During the first few months, it barely receives inquiries, but the script continues to load on all pages, even if no visitor ever opens the chat. That code continues to consume resources and can delay other more important interactions.

Whenever possible, it’s advisable to load these resources only when the user is going to use them. For example, a map can be displayed after pressing a button, and a YouTube video can initially be replaced by an image with a play button.

This way, the initial workload of the browser is reduced, and the site’s response capacity is improved.

Long tasks on the main thread

One of the most common causes of a high INP is the so-called long tasks on the main thread.

Although the name may sound complex, the idea is quite simple.

The browser works as if it had a single person attending a queue of tasks. While that person is busy solving one of them, they cannot respond to any other.

If at that moment a user clicks on a button, the browser cannot react until it finishes the work it already had pending.

That’s why, even if the button works correctly, the response comes late.

Long tasks usually occur when:

• Large blocks of JavaScript are executed.
• Huge amounts of data are processed in the browser.
• Multiple components are initialized at the same time.
• Complex operations are performed during page load.

The longer the main thread remains blocked, the worse the sense of fluidity during navigation.

Reducing these tasks, dividing them into smaller processes, or delaying those that are not critical usually has a very positive impact on interactivity.

Insufficient hosting or server

INP mainly depends on the work done by the browser, but that doesn’t mean the server is irrelevant.

A slow infrastructure can delay the delivery of essential resources, increase the time needed to generate the page, and cause the browser to start working later than desirable.

In other words, the server is not usually the direct cause of a bad INP, but it can worsen the context in which interactions occur.

For example, if a server takes too long to generate a dynamic page, the browser will receive the JavaScript files it needs to start executing the code later.

The same happens when the infrastructure has few resources, uses outdated PHP versions, or maintains saturated processes during peak traffic times.

That’s why improving front-end performance and having a solid technical foundation are two aspects that should always go hand in hand.

How to measure INP in WordPress

Before trying to optimize any metric, it’s advisable to know the real situation of the site.

Measuring INP allows you to identify which pages have problems, which elements affect interactivity the most, and whether the applied improvements actually produce results.

The recommendation is to combine tools that work with real user data and others oriented towards technical diagnosis.

PageSpeed Insights

PageSpeed Insights is usually the first starting point.

The tool analyzes a specific URL and shows both lab data and information from real users when available.

In addition to the INP value, it also offers recommendations related to:

• Long JavaScript tasks.
• Render-blocking resources.
• Third-party scripts.
• Main thread execution time.
• Front-end optimization opportunities.

It’s advisable to always review both the mobile and desktop versions, as behavior can vary significantly between the two devices.

In many projects, mobile presents worse results simply because it has less processing capacity.

Google Search Console

While PageSpeed Insights analyzes specific pages, Google Search Console allows you to detect trends at the entire site level.

Within the Core Web Vitals report, you can identify entire groups of URLs that present similar problems.

This is especially useful when managing a site with hundreds or thousands of pages, as it allows you to prioritize actions that will have the greatest impact.

Additionally, Search Console uses real data collected by Google, so it reflects the visitor experience quite accurately.

Lighthouse and diagnostic tools

Lighthouse is an excellent tool for locating the source of many interactivity problems.

Although its results are obtained in a controlled environment, it provides very useful information to detect:

• Excessively large JavaScript files.
• Long tasks on the main thread.
• Resources that block loading.
• Time spent executing scripts.
• Code that could be loaded deferred.

It should not be interpreted as an absolute score, but as a help to locate technical bottlenecks.

Chrome DevTools

When you need to delve even deeper, Chrome DevTools offers a very detailed view of what’s happening inside the browser.

Its Performance tab allows you to record all the activity of a page while you interact with it.

This way, you can check:

• Which scripts consume the most time.
• When the main thread is blocked.
• Which interaction causes a significant delay.
• How long it takes for the browser to respond again.

It’s an especially useful tool for developers or administrators who need to identify very specific problems during the optimization process.

How to reduce INP in WordPress step by step

Improving INP is not about applying a single change, but about eliminating the blockages that prevent the browser from responding quickly when the user interacts with the page.

In most WordPress projects, small optimizations spread across the front-end, plugins, and infrastructure produce better results than a single drastic modification.

Reduce and optimize JavaScript

JavaScript is usually the main culprit of a high INP.

Each file that is downloaded must be parsed, interpreted, and executed. If the browser has too much pending work, it will respond later to any user interaction.

Therefore, the first step to optimize WordPress JavaScript is to review which scripts are really necessary.

Whenever possible:

• Remove JavaScript files that are no longer used.
• Minify the code to reduce its size.
• Delay or defer the loading of non-critical scripts.
• Load each resource only on the pages where it is needed.

In many cases, a theme or a visual builder incorporates complete libraries for functionalities that are never used. Reducing that unnecessary code decreases the browser’s workload and improves response capacity.

It’s also advisable to review if some scripts can be loaded after the user’s initial interaction, instead of being executed during page load.

Review installed plugins

Not all plugins affect performance equally.

Some barely add a few lines of code, while others incorporate large amounts of JavaScript, style sheets, and additional queries even when their functionality is not being used.

A periodic audit usually reveals situations like these:

• Two plugins that perform practically the same function.
• Extensions installed for testing that were never removed.
• Plugins that stopped being used months ago.
• Functionalities already incorporated by the theme itself.

Reducing the number of plugins should not become a goal in itself. It’s perfectly possible to have an installation with many plugins and excellent performance.

What really matters is evaluating the impact each one has on the front-end.

Sometimes it’s more worthwhile to replace a very heavy plugin with a lighter one than to remove several whose influence is practically insignificant.

Limit the impact of third-party scripts

External tools are often responsible for much of the work the browser does.

That’s why it’s advisable to periodically review if all those services still add value.

It’s especially recommended to analyze:

• Marketing tags.
• Analytics tools.
• Online chats.
• Social widgets.
• Interactive maps.
• Embedded videos.
• Advertising platforms.

Whenever feasible, these resources should be loaded only when the user is going to use them.

For example, a map can initially be replaced by a static image and loaded only after clicking on it.

Similarly, many chats allow delaying their initialization until several seconds after the page loads or when the visitor starts interacting.

These small decisions reduce the browser’s initial workload and help reduce web interaction latency.

Use a light and well-optimized theme

The theme is one of the elements that most conditions the front-end behavior.

Some themes are designed to offer hundreds of customization options and compatibility with multiple visual builders.

That flexibility comes at a cost: more CSS files, more JavaScript, and more work for the browser.

If you’re starting a new project, it’s worth considering whether you really need a multipurpose theme or if a lighter theme will meet your needs.

The same goes for builders.

Tools like Elementor, Divi, or WPBakery allow creating complex pages with ease, but excessive use of widgets, animations, and dynamic elements can significantly increase the browser’s workload.

It doesn’t mean they should be avoided, but used with discretion.

Improve main thread performance

One of the keys to optimizing WordPress interactivity is to keep the browser’s main thread free.

Every time it executes a very long task, it temporarily stops attending to user actions.

Reducing that time involves:

• Dividing complex tasks into smaller processes.
• Avoiding initializing all components at the same time.
• Delaying secondary processes that are not critical.
• Reducing the amount of JavaScript executed during the initial load.

Many times, it’s not necessary to eliminate functionalities, but to better distribute the work the browser does.

Apply conditional resource loading

One of the most common mistakes in WordPress is loading all resources on all pages.

However, a contact form should only load its files where there is a form.

A slider only needs its scripts on the pages where it actually appears.

And an online calculator should not affect the rest of the site.

Conditional loading allows precisely that: serving each resource only when needed.

In projects with many multipurpose plugins, this practice usually generates very visible improvements both in INP and in overall performance.

Optimize forms, sliders, and pop-ups

Interactive elements are often the main culprits when interactivity problems arise.

Very complex forms, sliders with multiple animations, or pop-ups that execute as soon as the page loads can significantly increase the browser’s workload.

Before optimizing them, it’s worth asking a simple question:

Do they really add value to the user?

In many cases, the answer is negative.

Reducing unnecessary animations, simplifying forms, or removing intrusive pop-ups not only improves performance but also the browsing experience.

Sometimes, the best optimization is simply to remove what doesn’t add anything.

Implement cache and general optimization

Although INP mainly measures the browser’s response capacity, a fast environment makes the whole process smoother.

A good optimization strategy should also include aspects such as:

• Page cache.
• Browser cache.
• Brotli or Gzip compression.
• Resource minification when beneficial.
• Image optimization.
• Efficient delivery of static files.

If you haven’t reviewed these aspects yet, you can complement this article with our guide on web cache, where we explain how to reduce load time and improve the site’s overall performance.

Although these measures do not solve a bad INP on their own, they do contribute to creating a much more agile experience.

Review hosting and server configuration

Although INP mainly depends on the front-end, a modern infrastructure provides a much more solid foundation for the browser to respond quickly.

When the server takes too long to generate a page, slowly delivers static files, or uses outdated software versions, the whole process starts disadvantaged.

That’s why it’s worth reviewing aspects such as:

• Keeping PHP updated improves site security and reduces the time needed to generate dynamic pages.
• Having sufficient CPU and memory resources.
• Taking advantage of modern protocols like HTTP/2 or HTTP/3.
• Using Brotli or Gzip compression.
• Correctly configuring server-level cache.
• Incorporating a CDN when the audience is geographically distributed.

It’s important to remember that a CDN does not directly improve INP, but it does reduce the latency needed to download images, style sheets, and JavaScript files. This allows the browser to have the necessary resources to start processing interactions sooner.

In short, an optimized infrastructure does not replace work on the front-end, but it does create the right environment for all previous optimizations to have the greatest possible impact on the user experience.

Common mistakes when trying to improve INP

Optimizing INP is not about applying all possible techniques, but about identifying what is really slowing down your site’s response capacity.

These are some of the most common mistakes.

Focusing only on load speed

It’s easy to think that a fast website will always have a good INP, but that’s not necessarily the case.

A page can load in less than two seconds and still respond with a delay when the user clicks a button or tries to open a menu.

Load speed and interactivity are related, but they measure different aspects of performance.

Installing too many optimization plugins

There is a temptation to solve any problem by installing a new plugin.

However, combining several tools that minify files, manage cache, or modify JavaScript loading can have the opposite effect.

In addition to increasing site complexity, conflicts between them or duplicate optimizations often arise.

In most cases, it’s preferable to use a clear strategy and a few well-configured tools.

Not measuring before and after optimizing

If you don’t know what the initial problem was, you can hardly assess whether a modification has worked.

Every major change should be accompanied by a new measurement to check its impact.

Otherwise, you may spend hours optimizing elements that barely influence INP while the real bottlenecks remain.

Ignoring the impact of third-party scripts

Many audits focus solely on WordPress and forget to review external tools like advertising platforms, chats, tracking pixels, or social widgets.

In some projects, these services represent a significant part of the work the browser does.

Before looking for complex solutions, it’s worth asking if all those scripts are still necessary.

Optimizing only the homepage

It’s common for the home page to receive all the attention during an audit.

However, often the most visited pages are product pages, blog categories, or landing pages for advertising campaigns.

Each type of page can load different resources and present different problems.

That’s why it’s advisable to review those URLs that actually generate more traffic or conversions.

Confusing lab data with real data

An excellent score in Lighthouse does not guarantee that users are enjoying an equally good experience.

Lab tests are conducted under controlled conditions, while visitors access from very different devices, connections, and locations.

The ideal is to use Lighthouse to diagnose problems and Google Search Console to validate that improvements are also reflected in real data.

Applying optimizations without checking compatibilities

Delaying JavaScript loading or deferring certain scripts can significantly improve performance.

However, doing so without reviewing the site’s behavior can cause difficult-to-detect errors.

For example:

• Forms that stop submitting.
• Menus that don’t respond.
• Payment gateways that fail.
• Pop-ups that don’t appear.
• Functionalities that only stop working in certain browsers.

After any major optimization, it’s advisable to go through the main pages of the site and check that everything is still working correctly.

Relationship between INP, SEO, and user experience

INP is part of the Core Web Vitals in WordPress, a set of metrics that Google uses to evaluate page experience.

That doesn’t mean that improving this metric will automatically lead to an increase in search results positions.

SEO depends on many other factors, such as content quality, search intent, domain authority, or site architecture.

However, a website that responds quickly offers a better experience during navigation.

When a visitor perceives that buttons react immediately, forms work smoothly, and menus open without delays, the sense of quality and trust increases.

This improvement can translate into indirect benefits such as:

• Longer time on site.
• Less frustration during navigation.
• Better experience on mobile devices.
• Easier conversion completion.
• Greater overall user satisfaction.

In short, INP should not be understood as an isolated metric, but as another piece within a global strategy of WordPress web performance and user experience optimization.

Quick checklist to improve INP in WordPress

If you’re looking for a quick reference, this checklist summarizes the main actions you should review.

• Measure INP with PageSpeed Insights and Google Search Console.
• Identify long tasks on the main thread.
• Review the heaviest JavaScript scripts.
• Remove plugins that slow down WordPress.
• Apply conditional loading of CSS and JavaScript.
• Reduce the impact of third-party scripts.
• Use a light and well-optimized theme.
• Review forms, sliders, and pop-ups.
• Correctly configure the cache.
• Keep PHP updated.
• Verify that the hosting offers sufficient resources.
• Validate results with real user data.

Comparison of actions according to their impact on INP

Conclusion: improving INP is improving how your website feels

INP measures something that any user perceives immediately: the responsiveness of a page.

A website can load quickly and still be frustrating if each interaction takes too long to execute. Similarly, repeated small delays can convey a sense of slowness even when traditional load metrics are good.

The good news is that WordPress can offer a very smooth experience if the frontend is controlled and the elements that generate the most work in the browser are periodically reviewed.

Optimizing JavaScript, reducing the impact of plugins, reviewing third-party scripts, and using a light theme are some of the actions that most often influence this metric.

All of this is complemented by a well-prepared infrastructure. Keeping PHP updated, having optimized hosting, and using technologies like cache or a CDN do not solve a bad INP on their own, but they create the right environment for the browser to respond more quickly.

In short, improving INP is not about chasing a specific score, but about offering a more agile and pleasant navigation. And that benefits both your visitors and the overall performance of your project.

Frequently asked questions

What is INP in WordPress?

INP or Interaction to Next Paint measures the time it takes for a page to visually respond after the user performs an interaction, such as clicking a button or submitting a form.

What is a good INP value?

Generally, an INP below 200 milliseconds is considered good. Between 200 and 500 milliseconds needs improvement, and above 500 milliseconds, it is considered poor.

What causes high INP in WordPress?

The most common causes are excessive JavaScript, plugins that load too many scripts, third-party tools, overloaded themes, and long tasks that block the browser.

Does hosting affect INP?

Yes, although it’s not the only factor. Well-optimized hosting, with recent PHP versions, good server configuration, and sufficient resources, helps create a solid foundation to improve the site’s overall performance.

Which plugins usually affect INP the most?

Those that load a lot of JavaScript on the front-end, such as visual builders, sliders, advanced forms, online chats, pop-ups, tracking tools, or social widgets.

How can I measure the INP of my WordPress site?

You can use tools like PageSpeed Insights, Google Search Console, Lighthouse, or Chrome DevTools. It’s most recommended to combine lab data with real user data.

Does improving INP help SEO?

Yes, it is part of the Core Web Vitals and contributes to page experience. Additionally, a more responsive website usually offers a better user experience, which can positively impact behavior and conversion metrics.

Is INP the same as load speed?

No. Load speed measures how long it takes for a page to display, while INP evaluates how long it takes for that page to respond when the user interacts with it.