The verdict in three sentences
In Nairobi as in Ouagadougou, a major share of traffic arrives over 3G on entry-level phones: speed is therefore the first conversion factor. Each extra second of load time costs about 7 % of conversion, and a page over 3 seconds loses roughly 40 % of its visitors. Aim for an LCP under 2.5 seconds and a page weight under 500 KB by converting images to WebP.
The concrete impact of speed
A visitor on a slow network does not wait: they leave. Unoptimized images, heavy scripts and unnecessary custom fonts are the main culprits. Converting images to WebP cuts their weight by about 30 %, often the fastest win to get.
| Load time | 3G visitor loss | Conversion impact | Verdict |
|---|---|---|---|
| < 1.5 s | ~5 % | baseline | Excellent |
| 1.5-2.5 s | ~15 % | -7 % / s | Good |
| 2.5-3 s | ~30 % | -14 % | Needs work |
| 3-5 s | ~40 % | -21 to -35 % | Critical |
| > 5 s | > 50 % | collapse | Emergency |
The performance budget to hold
Optimizing means setting a resource budget and sticking to it. Every kilobyte counts on 3G. Here are the Core Web Vitals and weight targets for a high-performing store in 2026.
| Metric | 2026 target | Main lever | Typical gain |
|---|---|---|---|
| LCP (load) | < 2.5 s | WebP images, cache | -30 % weight |
| Total page weight | < 500 KB | compression, lazy load | -40 % bytes |
| CLS (stability) | < 0.1 | fixed image dimensions | stable UX |
| INP (responsiveness) | < 200 ms | lighter JS | +smoothness |
| HTTP requests | < 30 | file bundling | -latency |
Mini case study
Salif runs an appliance store in Nairobi. His product page loads in 4.5 seconds and converts at 1.2 %. After an audit and optimization (cost KES 60,000): WebP images, lazy loading, weight cut from 1.8 MB to 480 KB, LCP at 2.3 seconds. His conversion rises to 1.9 % (+58 %). On 8,000 monthly visitors and a 60,000 FCFA average basket, that is about 3,360,000 FCFA of extra sales per month.
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FAQ
Why does speed matter so much in Africa?
A large share of traffic arrives over 3G on modest phones. A slow page loses up to 40 % of visitors by 3 seconds, destroying conversion before the customer even sees the product.
What is the fastest win to get?
Converting images to WebP and lazy loading. On their own they cut weight by about 30 to 40 % and often save more than a second of load time.
Which targets to aim for in 2026?
An LCP under 2.5 seconds, page weight under 500 KB, CLS under 0.1 and INP under 200 ms. These Core Web Vitals thresholds are measurable and tracked over time.
How much does optimization cost in Nairobi?
A performance audit and optimization cost KES 30,000 to 80,000 (250,000 to 600,000 FCFA in Ouagadougou). The return comes from higher conversion, often 30 to 60 % on slow networks.
Let's talk about your project. We audit and optimize your store to convert on mobile and 3G. 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.
