Improve Core Web Vitals: fixing LCP, INP and CLS

Core Web Vitals optimization is not a single setting you flip, it happens metric by metric: you speed up loading (LCP), you make the page more responsive (INP) and you keep the layout stable (CLS). Every metric has its own causes and therefore its own fixes. In this article you will read, metric by metric, what to tackle concretely, how to check whether it works, and in which order to do it so that it moves your leads and not just a number.

Want to know first what LCP, INP and CLS actually measure and why Google factors them in? Read our explainer on what Core Web Vitals are. Here we go straight to the solutions.

What thresholds are you working towards?

You are aiming for three values: an LCP under 2.5 seconds, an INP under 200 milliseconds and a CLS under 0.1. Those are the limits Google labels as “good”.

• LCP (Largest Contentful Paint) measures how quickly the largest content block appears on screen, usually your hero image or a large heading.
• INP (Interaction to Next Paint) measures how quickly your page responds when someone clicks, taps or types. INP has been the official responsiveness benchmark since 2024 and replaced the older FID metric.
• CLS (Cumulative Layout Shift) measures how much the layout jumps around while the page loads.

Important to know before you start: Google judges these numbers on the 75th percentile of your real visitor data. In other words, at least three quarters of your visitors need to hit a good score. A nice lab measurement on your fast laptop therefore says very little; what counts is what your audience experiences on an average device and connection. That is why you always work from real data and never from a hunch.

How do you improve your LCP?

The fastest route to a better LCP is making your largest, first-visible element lighter and faster. In practice that is almost always an image, or a heavy loading process standing in its way.

Concrete fixes, in order of impact:

• Compress your images and use modern formats such as WebP or AVIF. A hero image of several megabytes is a classic LCP killer. Also serve visuals at the right dimensions instead of scaling a large file down in the browser.
• Get fast hosting and a CDN. A slow server keeps the browser waiting before anything appears at all. Hosting close to your audience, in this case usually Europe, makes a noticeable difference.
• Load your most important image with priority. With techniques like preloading you tell the browser that this visual needs to arrive first. Lazy loading has no place on your hero, because that delays exactly what you need.
• Limit what blocks the page. Heavy fonts, external scripts and unnecessary CSS that has to load first delay the moment your content becomes visible. The less the browser has to do before the first render, the better.

Much of this gain is technical work under the hood. It pays to get it right during the build or during a website redesign, because correcting it afterwards always costs more.

How do you make your INP better?

You improve INP by cutting back the amount and the weight of JavaScript, so the page is free to respond to a click quickly. A slow INP feels like a button that does not react, after which you click again in irritation.

What makes the difference:

• Prune third-party scripts. Trackers, chat widgets, A/B testing tools and marketing pixels stack up and keep the main thread busy. Remove what you do not really use and load the rest deferred.
• Break up heavy work. Long, uninterrupted chunks of JavaScript block every response. By splitting tasks up you give the browser room to respond to interactions in between.
• Be critical of heavy page builders and plugins. On WordPress especially, a pile-up of plugins and a heavy theme builder can wreck your INP. Less is often faster here.
• Keep forms light. Your contact and quote forms are exactly the places where interaction counts. A form that stutters at the moment someone wants to submit costs you a lead directly.

INP is the metric most strongly tied to how snappy your site feels. A page that responds instantly keeps people in the flow towards your conversion point.

How do you fix CLS?

You fix CLS by giving everything that takes up space a fixed spot in advance, so nothing jumps while the page loads. Shifting content is annoying and sometimes literally costs a misplaced click.

The most common causes and their fix:

• Visuals without fixed dimensions. Give every image and video a fixed width and height, so the browser reserves the space before the visual arrives. This is by far the most common source of layout shift.
• Ads, embeds and banners. Reserve a fixed block for content that loads later, such as an embedded map, video or cookie notice. That way it pushes nothing down.
• Fonts that load late. When a web font only appears later and the text reflows, your layout jumps. By loading fonts smartly and choosing a good fallback style, you limit that.
• Content injected at the top. A notification or bar that suddenly appears above your content pushes everything away. Plan space for it instead of shoving it on top.

CLS is usually the cheapest of the three to repair, because the fixes are often small and local. Still it often gets forgotten, precisely because it barely stands out on a fast development machine.

How do you check whether your improvements work?

You measure before and after, and you look at your real visitors, not just at a lab test. Otherwise you improve a number your audience never gets to see.

In practice you use two kinds of sources together:

• Field data (real visitors). Google Search Console shows the Core Web Vitals for your entire site based on actual user data, along with the URLs that need attention. This is your source of truth, because it is exactly what Google judges.
• Lab data (diagnostics). Tools like PageSpeed Insights and Google Lighthouse run a test in a simulated environment. Handy for seeing what slows a page down and for testing quickly, but the numbers fluctuate and they are a diagnosis, not a final verdict.

An approach that works: measure the current state, push a fix, and check in Search Console after a few weeks whether your field scores move along. Field data lags a bit because it is built up over a period, so do not expect a different number right after deploying. Always test on mobile too, because that is where the experience is usually heaviest and where the most gain is to be found.

Which fix do you tackle first?

Start with the metric that is furthest from the threshold on your most important pages and affects the most visitors. Not with whatever is technically the most fun to solve.

An honest order:

1. Look at which pages deliver traffic and leads. Your homepage, your most important website development page and your strongest landing pages weigh more heavily than a blog post buried deep in your site.
2. Tackle the metric that is in the red there. If your LCP sits at four seconds, image compression delivers more than clearing up one last CLS detail.
3. Take the cheap wins along the way. Fixed dimensions for visuals and removing a few redundant scripts cost little and help immediately.

Do not chase perfect scores. A page scoring 100 out of 100 that leads nobody to your form delivers nothing. The goal is for visitors to stay, click through smoothly and convert. Speed is a lever in that, not a finish line. Want to understand more deeply how this fits into a healthy, findable site? You will find the broader framework in our guide to building a B2B website.

The short summary

You improve Core Web Vitals metric by metric. For LCP it comes down to lighter images and fast hosting, for INP to less and lighter JavaScript, and for CLS to fixed dimensions so nothing jumps. Work from real visitor data in Search Console, use lab tools for diagnosis, and start with the pages and metrics that affect the most traffic and the most leads. That way a faster site does not become a goal in itself, but a direct way to convert more visitors.

Are your Core Web Vitals scoring badly and do you want to know where the real gain is? We map out what slows your site down and solve it at the root, with a focus on leads and revenue instead of vanity numbers. Schedule your free intake and you will hear where your opportunities lie.