The verdict in three sentences
Google ranks your pages and buyers judge your credibility on Core Web Vitals, and most East and West African stores fail them on mobile. Three metrics matter: LCP under 2.5s, INP under 200ms, CLS under 0.1. Holding them on throttled 3G improves both SEO ranking and conversion rate.
The thresholds to hit
Each metric measures something the buyer feels. Here are the official 2026 thresholds and what they mean:
| Metric | Good | Needs work | Poor | What it measures |
|---|---|---|---|---|
| LCP | < 2.5 s | 2.5-4 s | > 4 s | Speed of main content render |
| INP | < 200 ms | 200-500 ms | > 500 ms | Responsiveness to interactions |
| CLS | < 0.1 | 0.1-0.25 | > 0.25 | Visual stability (layout shifts) |
| TTFB | < 0.8 s | 0.8-1.8 s | > 1.8 s | Server response time |
A typical unoptimized store shows an LCP of 5-8s and a CLS of 0.3: it fails all three.
Failing store vs tuned store
The fixes are known and targeted. Before/after comparison and remediation:
| Point | Failing store | Tuned store | Fix |
|---|---|---|---|
| LCP | 6.4 s | 2.2 s | Preload hero image, CDN, WebP |
| INP | 420 ms | 140 ms | Trim JavaScript, defer non-critical |
| CLS | 0.32 | 0.04 | Reserve image/ad space, font-swap |
| Fonts | Render-blocking | font-swap | Load font without blocking text |
| Testing | Office fiber | Throttled 3G | Test worst case, not best |
Testing on throttled 3G is the key: that is your buyers' reality, not your agency's fiber.
Mini case study
Ibrahim sells electronics in Nairobi. His store shows LCP 6.1s, INP 380ms, CLS 0.29: it sits on page 3 for "refurbished phone Nairobi" and converts at 1.1%. After tuning (LCP 2.3s, INP 150ms, CLS 0.05), it climbs to page 1 and converts at 1.7%. On 8,000 mobile visits/month that is 48 extra orders; at 35,000 FCFA margin per sale, that is 1,680,000 FCFA in extra monthly margin.
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FAQ
Do Core Web Vitals really affect ranking?
Yes, they are part of Google's page experience signals. All else equal, the faster and more stable store ranks ahead, especially on mobile.
What exactly is INP?
INP measures the delay between the buyer's click or tap and the visible response. Under 200ms the interaction feels instant; beyond, the page feels sticky.
How do I reduce CLS?
By reserving space for images, banners and ads before they load, and using font-swap. Content no longer jumps while the buyer reads.
Which tool should I measure with?
PageSpeed Insights and Lighthouse in mobile throttled-3G mode, complemented by field data (CrUX) that reflects your real visitors.
How long to fix everything?
For a standard store, 1 to 3 weeks depending on technical debt. LCP and CLS gains often land in the first week.
Let's talk about your project. We measure your three Core Web Vitals on 3G and deliver a costed remediation plan. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
