The verdict in three sentences
A Core Web Vitals audit plus optimization costs between EUR 3,000 and EUR 12,000 in 2026, for a 3-to-6-week project depending on site size. The technical targets are clear: LCP < 2.5s, INP < 200ms, and CLS < 0.1, thresholds Google rates as "good." The payoff: a digital manager in Bordeaux can target up to +15% organic traffic and a conversion rate rising 7 to 20% once the slowness is fixed.
What a CWV audit includes in 2026
A slow B2B site loses rankings and money: every second of LCP above 2.5s degrades engagement and ranking. The audit measures the three metrics on field data (CrUX) and lab data (Lighthouse), pinpoints bottlenecks (unoptimized images, blocking JavaScript, slow server), and delivers a prioritized action plan.
| Service | 2026 price (EUR excl. VAT) | Duration | Scope |
|---|---|---|---|
| Audit only | 3,000 - 5,000 | 3 weeks | Diagnosis + prioritized plan |
| Audit + light optimization | 5,000 - 8,000 | 4 weeks | Images, cache, lazy-load |
| Audit + full optimization | 8,000 - 12,000 | 5-6 weeks | Front-end, server, JS rework |
| Post-audit monthly monitoring | 500 - 1,200/month | Ongoing | Monitoring + fixes |
The fastest wins often come from the LCP image (AVIF/WebP format, sizing, preload) and reducing third-party JavaScript, two levers that alone can shave 1 to 2 seconds off LCP.
Quantified business impact
| Metric | Before audit | After optimization | Gain |
|---|---|---|---|
| LCP | 4.2s | 2.1s | -50% |
| INP | 380ms | 160ms | -58% |
| CLS | 0.24 | 0.05 | -79% |
| Organic traffic | Base 100 | 108 - 115 | +8 to +15% |
| Conversion rate | 1.8% | 1.95 - 2.15% | +7 to +20% |
| Bounce rate | 58% | 44 - 50% | -8 to -14 pts |
These 2026 orders of magnitude assume an initially degraded site (LCP > 4s). On an already-decent site, SEO gains are more modest, but user comfort and conversion still improve.
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Mini case study
Thomas, digital manager at a B2B software vendor in Bordeaux, sees a 3-position drop on his key queries and an LCP at 4.4s. He orders an audit + full optimization at EUR 9,500 over 5 weeks. Result: LCP down to 2.0s, INP to 150ms, organic traffic +12%, and conversion rate up from 1.7% to 2.0%. On 45,000 visitors/month, the 0.3-point conversion gain generates 135 extra conversions/month. At an average value of EUR 90 per lead, that is EUR 12,150/month in added value, a return on investment in under a month.
FAQ
What's the difference between audit-only and audit + optimization? The audit-only (EUR 3,000-5,000) delivers a diagnosis and plan for your team to execute. The full offer includes technical implementation, essential if you lack an available front-end developer.
How long to see SEO impact? Core Web Vitals are recalculated on a rolling 28-day window on Google's side (CrUX data). Expect 4 to 8 weeks after optimization for the ranking effect to stabilize.
Is INP really a ranking factor? Yes, since March 2024 INP replaced FID as the official interactivity metric. An INP above 200ms hurts experience and, over the long term, rankings.
Is monitoring needed after the audit? Strongly recommended: every deployment, plugin, or marketing script can degrade the metrics. Monitoring at EUR 500-1,200/month prevents silent regression.
Is a good Lighthouse score enough? No: Lighthouse measures in the lab, but Google ranks on real field data (CrUX). A site can show 95 in the lab and fail in the field due to slower devices and networks.
Let's scope your project. Share your site URL, CMS, and current metrics, and we'll price a CWV audit and its optimization (EUR 3,000 to 12,000). 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.
