The verdict in three sentences
Across many emerging markets, a large share of traffic still runs on 3G, where a 3 MB site takes 12 seconds to render and drives visitors away. In 2026, a brochure site built for 3G targets page weight < 500 KB, LCP < 3 s on 3G and an offline-first PWA mode, for a budget equivalent to 400,000 to 1,000,000 FCFA. The golden rule: every second of load time cut wins back roughly +7 % of conversions.
The weight that kills conversions on 3G
On real 3G (~1.5 Mbps throughput, high latency), page weight determines everything. Here is the estimated load time by weight and its business impact.
| Page weight | 3G load time | Bounce rate | Conversions |
|---|---|---|---|
| 3,000 KB | ~12 s | 65 % | baseline -0 |
| 1,500 KB | ~7 s | 48 % | +18 % |
| 800 KB | ~4 s | 32 % | +35 % |
| 500 KB | ~2.8 s | 22 % | +48 % |
| 300 KB | ~1.9 s | 16 % | +55 % |
The math is simple: going from 3 MB to 500 KB drops load time from 12 to under 3 seconds. At roughly -7 % conversions per second lost, you recover most of the visitors who abandoned before even seeing the page.
The techniques and their 2026 cost
A light site is not a poor site: it is one where every kilobyte is justified. Here are the levers and their cost.
| Technique | Effect | 2026 cost (FCFA equiv.) |
|---|---|---|
| WebP/AVIF images + srcset | Image weight -70 % | 80,000 - 200,000 |
| Offline-first PWA | Offline browsing | 150,000 - 350,000 |
| Edge cache / CDN | Latency -60 % | 60,000 - 150,000 |
| Inline critical CSS/JS | First paint < 2 s | 70,000 - 180,000 |
| Weight budget (< 500 KB) | Anti-regression | 50,000 - 120,000 |
| System fonts (no webfont) | -100 KB | included |
The offline-first PWA is a decisive asset in emerging markets: the site caches on the visitor's phone from the first visit and stays browsable even during a network drop. For a merchant, it guarantees that hours, catalogue and WhatsApp number stay accessible offline.
Performance targets to hold
A 3G-ready brochure site must meet measurable thresholds, verified on a real 3G network, not just in the lab.
| Target | 2026 value | Why |
|---|---|---|
| Page weight | < 500 KB | Load < 3 s on 3G |
| 3G LCP | < 3 s | Visitor retention |
| HTTP requests | < 20 | Cumulative latency |
| Images | WebP/AVIF, lazy | -70 % weight |
| Offline mode | PWA cache | Network drops |
Mini case study
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Kolonell builds websites that attract clients, optimized for the Sénégalese market. Free quote in 2 minutes.
Issa, who runs an appliance store serving an emerging market from Miami, had a 3.1 MB site that took 13 seconds to load on 3G; 6 in 10 visitors left before it rendered. His lightweight rebuild is quoted at the equivalent of 650,000 FCFA: WebP images, offline PWA, edge cache, weight budget at 480 KB. Result: LCP at 2.6 s on 3G, bounce from 62 % to 24 %. With 1,500 visits/month and a WhatsApp contact rate rising from 3 % to 7 %, he gets about 60 more enquiries/month. At an average basket of 45,000 FCFA and 20 % conversion, the investment pays back in under 2 months.
FAQ
Why target under 500 KB per page?
Because on real 3G, every hundred kilobytes adds nearly a second of load time. Under 500 KB, the page renders in less than 3 seconds and holds the visitor.
What is an offline-first PWA site?
A web app that caches on the phone from the first visit and stays browsable without network. Ideal where 3G often drops.
How much does a 3G-ready brochure site cost in 2026?
Between the equivalent of 400,000 and 1,000,000 FCFA depending on page count and features (PWA, form, WhatsApp). An optimised 5-page site sits at the low end.
Is a light site less attractive?
No. Lightness comes from technical optimisation (WebP images, lean code), not from sacrificing design. A fast site even feels more premium.
What does a faster site actually earn?
About +7 % conversions per second of load time saved. Going from 12 to 3 seconds can more than double the mobile 3G contact rate.
Let's scope your project. Tell us your page count, needs (PWA, WhatsApp, form) and budget: we will quote an ultra-fast brochure site built for 3G. Detailed quote within 48 h. 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.
