If your website is slow on a 4G connection in Kampala, you're losing customers before they even see your pricing. Core Web Vitals are Google's way of measuring exactly this, and in 2026 they're still one of the clearest signals separating sites that rank from sites that don't. Here's what the three metrics mean and where to start if you're failing them.
What are Core Web Vitals?
Core Web Vitals are three speed and stability measurements Google uses as part of how it ranks websites. They were introduced to push developers to care about real-world user experience, not just lab scores. Passing them doesn't guarantee first-page rankings, but failing them puts a ceiling on how well your other SEO work can perform.
The three metrics that matter
Largest Contentful Paint (LCP)
LCP measures how long it takes for the biggest piece of content on your page, usually a hero image or headline, to finish loading. Google wants this under 2.5 seconds. Most websites we audit are sitting between 4 and 8 seconds, almost always for the same reasons:
- Unoptimised hero images (5MB JPGs loaded on mobile)
- Shared hosting with slow server response times from distant data centres
- Render-blocking scripts running before the hero image can load
- No CDN, so every visitor's browser downloads files from a server far away
Fixing LCP usually starts with the hosting and image pipeline, not with code. If your server is responding in over 1 second, no amount of code optimisation will make up for it.
Interaction to Next Paint (INP)
INP replaced First Input Delay in 2024 and measures how quickly your page responds to any click, tap, or key press throughout the entire session, not just the first one. Google's threshold is under 200ms. The things that break it most often:
- Large JavaScript bundles blocking the main thread
- Third-party scripts (chat widgets, marketing pixels) running at the wrong time
- Heavy animations or layout calculations triggered by user interaction
- Client-side rendering of content that should have been server-rendered
Cumulative Layout Shift (CLS)
CLS measures visual stability: whether elements jump around as the page loads. You've seen this before. You go to tap a button and the page shifts just as you click, so you end up on the wrong link. Google wants a CLS score under 0.1. Common causes:
- Images without defined width and height attributes
- Ads or embeds loading late and pushing content down
- Custom fonts causing a flash of unstyled text that shifts the layout
- Dynamic content injected without reserving space first
How to check your Core Web Vitals for free
All of this is measurable without spending anything. Start with these:
- PageSpeed Insights (pagespeed.web.dev): paste your URL, get a real-world and lab score with specific issues called out
- Google Search Console: under Experience > Core Web Vitals, see which pages are passing or failing based on real user data
- Chrome DevTools: run a Lighthouse audit in the browser to see your scores
Always test on mobile and on a simulated slow connection. Your office WiFi is not your customer's internet.
What we see most often on Ugandan business websites
After auditing dozens of sites for clients across Kampala, these are the issues that come up most:
- Hero images over 2MB loaded as standard JPGs with no compression
- Websites hosted on old shared hosting with server response times over 2 seconds
- No caching or CDN set up, so every page load hits the origin server directly
- Plugins and scripts added over time that nobody ever cleaned up
- Sites built on page builders that produce bloated HTML and CSS
None of these are expensive to fix. They're just easy to ignore until someone asks why the site isn't ranking.
Where to start
Don't try to fix everything at once. Run PageSpeed Insights on your homepage and your most important service or product page. Fix LCP first because it has the biggest impact. Then work through INP and CLS. If your server response time is over 600ms, fix hosting before touching anything else.
If you want us to take a look, get in touch and we'll run a quick audit and tell you exactly what's worth fixing.
