Around half of mobile visitors leave a page that takes longer than three seconds to load. Google also uses page experience as a ranking signal, so speed affects both your leads and your visibility. The good news: most slow sites can be made dramatically faster with a handful of well-chosen fixes.
This guide explains what Google measures, which scores to aim for, and where to start.
What Core Web Vitals measure
Core Web Vitals are three metrics Google uses to judge real-world user experience. They're measured on real visitors' devices, not just in a lab test.
- LCP (Largest Contentful Paint) — how quickly the main content appears. Aim for under 2.5 seconds.
- INP (Interaction to Next Paint) — how fast the page reacts to taps and clicks. Aim for under 200 ms.
- CLS (Cumulative Layout Shift) — how much the layout jumps while loading. Aim for under 0.1.
Why mobile matters most
Most of your visitors are probably on mid-range Android phones over 4G. A site that feels fast on an office laptop can be painfully slow there — always test on mobile first.
The fixes that matter most
Optimise images
Images are usually the heaviest part of a page. Serve modern formats like WebP or AVIF, size images for the screen they're shown on, compress them properly and lazy-load anything below the fold. The main hero image should load first, with high priority.
Reduce JavaScript
Heavy page builders, chat widgets, sliders and unused plugins slow down interaction. Frameworks like Next.js ship only what each page needs and pre-render pages so content appears immediately.
Reserve space for content
Set width and height on images, ads and embeds so the layout doesn't jump as they load. Load web fonts with a fallback so text doesn't suddenly change size.
Use good hosting and caching
A fast server close to your visitors, a CDN for images and files, and proper browser caching can cut load times in half without changing a line of design.
A fast website is not a technical luxury — it's the first impression of your brand.
Third-party scripts: the hidden cost
Every tracking pixel, chat widget and embedded video adds weight. Audit them regularly and remove anything you don't actively use. Load the rest after the main content, not before.
- List every script running on your site.
- Remove duplicates and anything no longer needed.
- Load marketing tags through Google Tag Manager with sensible triggers.
- Replace heavy embeds with lightweight previews that load on click.
Measure, then improve
Check your site in PageSpeed Insights and the Core Web Vitals report in Google Search Console. Fix the biggest issues first, re-test after every change, and keep an eye on the numbers each month — new content and plugins can slowly undo good work.
What results to expect
For most of our clients, moving from a slow page builder site to an optimised Next.js site brings load times from 6–8 seconds down to under 2, with noticeably lower bounce rates and more enquiries from the same traffic.
Want a faster site? Our website development team can audit and speed it up.
