Core Web Vitals for Kenyan Websites: The Three Numbers, and How to Find Yours Free

Somebody taps your link from a WhatsApp group while standing in traffic on Mombasa Road. Their phone is two years old and the cell they are on is busy. You have a few seconds before they go back to the group.

Core Web Vitals are Google's attempt to measure exactly that moment, in three numbers. They are worth understanding not because Google says so, but because on a Kenyan mobile connection the difference between a fast page and an average one is the difference between a reader and a bounce.

The Three Numbers

Each one measures a different kind of annoyance.

CLS is the one business owners recognise instantly once it is named. You go to tap "Menu", an advert finishes loading above it, everything slides down, and you tap something else. That is a layout shift, and it is measured.

The Part Everybody Misses: the 75th Percentile

Google does not take your average visitor. It takes the 75th percentile, which means three quarters of your visits have to be in the good range for the metric to pass.

That distinction matters more in Kenya than in most markets. If your site is quick for people in the office on fibre and slow for people on mobile data in Kisii, an average hides the problem and the 75th percentile exposes it. You are being graded on your slower visitors, which is the right way round, because they are the ones leaving.

INP Replaced FID, and It Is Harsher

Until March 2024 the responsiveness metric was First Input Delay, which measured only the delay on the very first interaction in a visit. That flattered almost everybody, because the first tap often happens before the heavy scripts have finished arriving.

INP looks at responsiveness across the whole visit and reports close to the worst of it. A page that passed comfortably under FID can fail under INP, with nothing having changed except the measurement.

Why Kenyan Sites Are Judged Differently

The metrics are the same everywhere. The conditions are not.

Google's assessment uses field data: real visits, from real devices, on real connections. For a Kenyan business that means mid-range Android phones on mobile data, often with the browser already holding several tabs, sometimes on a cell that is busy. Nothing about that resembles a developer's laptop on office fibre.

Two practical consequences. First, the heavy hero video that looks magnificent in a design review is a liability. Second, anything loaded from a distant server, fonts especially, costs more here than it does in London, because every extra connection pays the full round trip.

Check Yours in About a Minute, Free

You do not need to guess at any of this, and you do not need to pay anyone to find out.

Test on a phone over mobile data too, not only in a tool. Thirty seconds of using your own site on your own phone away from the wifi tells you things no score does.

What Is Usually Wrong

In rough order of how often we find each one on a Kenyan WordPress site:

1. Images straight from a camera or phone. A 4MB photograph displayed at 600 pixels wide. This single issue accounts for more failures than everything below it combined.
2. A page builder loading everything. Many builders ship the scripts and styles for every feature they offer on every page, whether or not the page uses them.
3. Plugin sprawl. Twenty-six plugins, each adding a file or two, several doing a job nothing on the site needs any more.
4. Fonts from somebody else's server. An extra connection before any text can be drawn.
5. Chat widgets, pixels and tag managers. Each one small, all of them together not small, and most of them competing for the same moment.
6. Hosting with no caching in front of it. Every visitor made to wait while the page is rebuilt from scratch.

Fixing It, in the Order That Pays

You rarely need to do all of it. The first three steps usually move a failing site into the good range.

Then measure again, on a phone, on mobile data. Our guides to speed optimisation and the plugins worth using go deeper on the how.

What This Does and Does Not Do for Rankings

Core Web Vitals form part of how Google assesses page experience. They are a tie-breaker between pages that are otherwise comparable, not a trump card. A fast page about the wrong subject will not outrank a slower page that genuinely answers the question.

So do not fix your speed expecting rankings to transform. Fix it because of what happens in the seconds before anyone reads a word: on a Kenyan mobile connection, a page that takes six seconds has lost a share of its visitors before they ever saw what you sell. That is the number that pays for the work.

Frequently Asked Questions

What are the Core Web Vitals and what counts as good?

Three measurements of what a visitor experiences. LCP, how long until the main thing on screen has loaded, is good at 2.5 seconds or less and poor above 4 seconds. INP, how quickly the page responds when somebody taps or clicks, is good at 200 milliseconds or less and poor above 500. CLS, how much the layout jumps about while loading, is good at 0.1 or less and poor above 0.25. Google judges each at the 75th percentile of real visits, so three quarters of your visitors have to be in the good range.

What happened to First Input Delay?

INP replaced FID as a Core Web Vital in March 2024. FID measured only the delay on the first interaction of a visit, which flattered most pages. INP looks at responsiveness across the whole visit and reports close to the worst of it, so a page that felt fine under FID can score badly under INP. If your last performance review predates 2024, it measured something that no longer counts.

Do Core Web Vitals affect Google rankings in Kenya?

They are part of how Google assesses page experience, but they are a tie-breaker rather than a trump card. A fast page about the wrong thing will not outrank a slow page that answers the question. The stronger argument for fixing them is commercial: on Kenyan mobile data, a page that takes six seconds loses people before they see anything you wrote, whatever Google thinks.

Why does my site score well on my laptop but badly in the real report?

Because the two measure different things. A test run from your browser on office fibre is a laboratory result. Google's assessment uses field data from real visits on real devices, which for a Kenyan site means mid-range Android phones on mobile data, sometimes on a congested cell. Always believe the field data over the lab score, and test on a phone over mobile data before you declare anything fixed.

What usually causes a slow Kenyan website?

In order of how often we find it: enormous unresized images, a page builder loading scripts and styles for features the page does not use, too many plugins each adding their own files, fonts loaded from someone else's server, chat widgets and tracking scripts, and hosting far from the visitor with no caching in front of it. The first two account for most of it on the average WordPress site.

How can I check my own Core Web Vitals for free?

Run our free PageSpeed test at wpfoss.ke/pagespeed-test, which gives you the numbers for a page in about a minute with no signup. Our website checkup at wpfoss.ke/website-checkup scores the whole site, including speed alongside mobile setup, HTTPS and whether Google can read your pages. Google Search Console also has a Core Web Vitals report using your own visitors' data, which is the most honest source of all once you have enough traffic.