Core Web Vitals Checklist for Marketing Sites

Picture this. Your ad is working. Someone taps it, and then they sit watching a blank screen for four seconds, the page jumps as a banner loads, and they hit the back button before they've read a word. You paid for that click. Your website threw it away.

It happens more often than most teams realise, especially on landing pages that were built quickly and then loaded up with chat widgets, trackers and heavy images. Google measures this experience with three numbers called Core Web Vitals, and they're one of the easiest places to find quick wins.

This checklist is written for marketing and lead-generation sites, such as real estate project pages and EdTech course pages. Some fixes you can do yourself in an afternoon. For the rest, our website development and CRO services can help.

Core Web Vitals in plain English

There are three, and each answers a simple question. Google's "good" targets are measured on real visitors, at the 75th percentile.

• LCP (Largest Contentful Paint): How fast does the main content show up? Aim for 2.5 seconds or less.
• INP (Interaction to Next Paint): How quickly does the page respond when someone taps or clicks? Aim for 200 milliseconds or less.
• CLS (Cumulative Layout Shift): Does the page jump around while loading? Aim for 0.1 or less.

Before you fix anything, measure it properly

Guessing wastes time. Start here:

1. Run your key landing pages through PageSpeed Insights. Look at the "field data" first, which comes from real users, and use the lab data as a guide to what to fix.
2. Open the Core Web Vitals report in Google Search Console. It groups your URLs into good, needs improvement and poor, so you can fix whole groups of pages at once.
3. Test on a mid-range phone over mobile data, not just your office laptop on Wi-Fi. That's closer to what your visitors actually see.

Write down your starting numbers. You'll want them later.

LCP: get the main content on screen fast

On most marketing pages, the slowest element is the hero image or the headline font.

• Compress the hero image and use a modern format such as WebP or AVIF.
• Set explicit width and height on hero media so the browser can reserve space.
• Preload the LCP image, and don't lazy-load it. Lazy loading is for images below the fold.
• Self-host critical fonts, or use font-display: swap with a sensible system font as a fallback.
• Check your server response time. A slow server slows everything else down, and a CDN often helps.

CLS: stop the page from jumping

Nothing annoys a visitor more than tapping a button just as it moves. The usual culprits are cookie banners, chat widgets, late-loading images and ads.

• Give images, videos and embeds fixed dimensions.
• Reserve space for banners and widgets with a minimum height, so they don't push content down when they appear.
• Never insert content above existing content after the page has started rendering.
• Make sure your fallback font is close in size to your main font, so the text doesn't shift when the font loads.

INP: keep the page responsive

If a page looks ready but reacts slowly, the cause is usually too much JavaScript, and much of it is third-party.

• Audit your scripts. Heatmaps, chat tools, tag managers and old tracking pixels pile up quickly.
• Remove what you don't use, and load the rest after the first interaction or when the browser is idle.
• Break up long tasks and avoid heavy sliders and animations on landing pages.
• Test your forms. A form that lags when someone types or submits costs you leads directly.

Extra checks for lead-generation landing pages

A landing page has one job, which is to get the enquiry. A few extra checks help:

• Keep the first screen light: one clear headline, one image, one form or button.
• Make sure the call and WhatsApp buttons work instantly on mobile.
• Be careful with pop-ups and sticky bars that cover the form or cause layout shifts.
• Give every project or course its own page. Our guide to building a landing page for every project shows why.

Why it matters for SEO and for paid traffic

For organic search, page experience is one of many signals. Relevance and content quality still come first, so don't expect speed alone to move you up. But when two pages are equally relevant, the faster, steadier one has the edge, and a slow page loses visitors long before Google notices. If you want a team to handle this alongside content and links, see our SEO agency work, including real estate SEO and EdTech SEO.

For paid traffic, the landing page experience is part of how Google Ads judges your ads, and a slow page wastes budget directly. That's why speed is the first thing we check in our Google Ads services.

Treat speed fixes like any other test

Change one thing at a time, note the result and keep a log. If you've set up a performance marketing test plan, add your speed changes to it, so you can see which fix actually raised your conversion rate.

Quick checklist

• Measure key pages in PageSpeed Insights and Search Console
• Compress and resize hero images, and preload the main one
• Self-host critical fonts with a good fallback
• Set dimensions on all images, videos and embeds
• Reserve space for banners and widgets
• Remove or delay unused third-party scripts
• Test forms and buttons on a mid-range phone
• Re-check your numbers after each change

Mistakes to avoid

• Testing only on a fast office connection
• Lazy-loading the hero image
• Adding another tracking tool without removing the old ones
• Fixing everything at once, so you can't tell what worked
• Chasing a perfect score instead of fixing the pages that bring in leads

FAQs

What are the three Core Web Vitals?

LCP measures how quickly the main content loads, INP measures how quickly the page responds to taps and clicks, and CLS measures how much the layout shifts while loading.

Do Core Web Vitals affect Google rankings?

They're one signal within Google's page experience, so they can help, but relevance and content quality matter more. They also affect conversions directly, because slow or jumpy pages lose visitors.

How often should I check them?

Monthly, and again whenever you add a new script, widget or page template.

Can I fix Core Web Vitals without a developer?

Some fixes are easy: compressing images, removing unused plugins and scripts, and setting image dimensions. Others, like preloading, font handling and reducing JavaScript, usually need a developer.

Want your landing pages faster and converting better?

If you'd like us to audit your site's speed and fix what's holding back your leads, talk to our website development team.