The verdict in three sentences
For a CFO, web performance is not a technical cost but an investment with measurable ROI. Moving a Lighthouse score from 55 to 92 costs 5,000 to 12,000 EUR and lets you observe +18 to 35 % more leads on a B2B site. The lever is simple: a fast site reduces bounce, improves ranking and mechanically increases the number of quote requests.
What a performance optimization costs in 2026
Price depends on the starting state, the tech stack and the scope of fixes. A WordPress site overloaded with plugins requires more work than an already well-built site.
| Service | Price (EUR) | Typical Lighthouse gain |
|---|---|---|
| Light optimization (images, cache, CDN) | 2,500 - 4,000 | +15 to 25 pts |
| Full optimization (JS, CSS, fonts, LCP) | 5,000 - 8,000 | +25 to 35 pts |
| Technical rebuild (headless, SSR) | 8,000 - 12,000 | +35 to 45 pts |
| Performance monitoring (RUM) | 150 - 400 / month | score maintenance |
| Continuous optimization (retainer) | 800 - 2,000 / month | progressive improvement |
Before / after: the quantified business impact
Performance shows up in business metrics, not just a technical score. Here is a typical 2026 transformation observed on a B2B site.
| Indicator | Before | After | Change |
|---|---|---|---|
| Mobile Lighthouse score | 55 | 92 | +37 pts |
| Average page weight | 4 MB | 900 KB | -78 % |
| Load time (LCP) | 5.2 s | 1.9 s | -63 % |
| Bounce rate | 61 % | 42 % | -19 pts |
| Conversion rate | 1.6 % | 2.1 % | +31 % |
| Monthly leads | 96 | 126 | +31 % |
These values are 2026 orders of magnitude from B2B optimization projects; real gains depend on traffic and funnel quality.
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Mini case study
Claire is CFO of an industrial SMB in Lyon receiving 10,000 visits/month. The site plateaus at 1.6 % conversion. She approves an optimization budget of 8,500 EUR. After the work, conversion rises to 2.1 %, or 50 additional leads/month (from 160 to 210). At a 10 % close rate and a 7,000 EUR average deal, that adds 5 new clients/month, or 35,000 EUR in additional monthly revenue. The investment is repaid in under a week of billing, and the gain continues every month at no marginal cost.
FAQ
Does a fast site really increase B2B sales? Yes, the effect is twofold: better Google ranking and fewer abandonments. 2026 studies observe +18 to 35 % more leads when a site moves from a poor score to a green one.
Should I rebuild or optimize the existing site? It depends on technical debt. A 5,000-8,000 EUR optimization is often enough; a full technical rebuild (8,000-12,000 EUR) is justified if the base is unmanageable or obsolete.
How do I justify the budget to management? With ROI math: current traffic x conversion gain x close rate x average deal. The extra cost is usually repaid within a few weeks of additional leads.
Is the performance gain durable? Yes, if maintained. Every added feature or tracking script can degrade the score; RUM monitoring at 150-400 EUR/month protects the investment.
What is the timeline for an optimization project? From 2 to 6 weeks depending on scope. A light optimization ships in 10 days; a full technical rebuild takes up to 8 weeks with QA and testing.
Let's scope your project. Send us your current Lighthouse score, your monthly traffic and your conversion rate: we quote the optimization and project the expected ROI. 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.
