What LCP, INP and CLS mean, how to check your site in five minutes and which fixes deliver the fastest results.
You pay for an ad, someone clicks it — and stares at a white screen. Two seconds, three, four… and they go back to the search results, to a competitor. A slow site quietly eats your ad budget and search rankings. Here’s how to measure speed, what Core Web Vitals mean and what actually makes a site faster.
Why speed is money
- Conversion. Every extra second of loading increases the share of visitors who leave before the page appears — especially on mobile data.
- Ads. You pay for the click even if the person left before the page loaded. A slow landing page makes every lead more expensive.
- SEO. Google takes page speed and experience signals into account when ranking.
Core Web Vitals in plain words
Core Web Vitals are three Google metrics that describe how comfortable a page is to use:
LCP — main content loading
How many seconds until the largest element appears on screen: the hero banner, a product photo, the headline. Good — under 2.5 seconds.
INP — responsiveness
How quickly the page reacts to actions: tapping a button, opening a menu, adding to cart. Good — under 200 milliseconds. If nothing happens after a tap, people tap again — or leave.
CLS — visual stability
How much content “jumps” while loading. You know the feeling: you go to tap a link, an image loads, and you hit an ad banner instead. Good — under 0.1.
How to check your site
- Open PageSpeed Insights (pagespeed.web.dev) and enter your site’s address.
- Look at the “Mobile” tab first — that’s where most of your customers are.
- Pay attention to the real-user data block: it shows how the site performs for actual visitors, not in a lab test.
- Check key pages too, not just the home page: product page, service page, checkout form.
Google Search Console has a “Core Web Vitals” report that shows problem page groups across the whole site.
What usually slows a site down
Heavy images
5 MB photos straight from a camera are the main cause of slow sites. Images should be compressed, converted to modern formats (WebP, AVIF), served in different sizes for phones and desktops, and lazy-loaded — only when the visitor scrolls to them.
Unnecessary scripts
Chats, callback widgets, multiple counters, pixels for every ad network, sliders — each script adds weight and delay. Audit them: is all of it actually used?
Weak hosting
If the server takes more than a second to respond, image optimization won’t save you. Online stores and high-traffic sites need a proper VPS, caching and a server located close to the audience.
Fonts and heavy themes
Ready-made themes for site builders and WordPress often load dozens of files the page never uses. Five font weights instead of two add several hundred more kilobytes.
Quick wins
- Compress images and convert them to WebP.
- Enable caching and compression on the server.
- Remove unused widgets and scripts.
- Set dimensions for images and banners so content doesn’t jump.
- Use a CDN if your audience is spread across countries.
Speed is built in during development. We design sites to land in the Core Web Vitals “green zone” before launch.
If your site is slow and you’re not sure why, order a technical audit. We’ll show exactly what’s slowing it down and how much the fix will cost.
