The verdict in three sentences
A thorough Core Web Vitals audit with an optimization plan costs between 3,500 and 9,000 EUR HT in 2026 and runs over 3 to 5 weeks. Typical gains for a slow B2B site: LCP brought under 2.5 s, INP under 200 ms, CLS under 0.1, with a bounce rate down about 22 %. To sustain performance over time, plan for performance maintenance of 300 to 600 EUR HT/month covering CDN, monitoring and a fix budget.
The three metrics and what you can gain
Google assesses experience via three measurable signals. A slow B2B site loses positions and organic traffic. Here is a before/after order of magnitude for a Berlin mid-cap with a showcase site plus catalog.
| Metric | "Good" threshold | Before audit | After optimization | Main lever |
|---|---|---|---|---|
| LCP (loading) | < 2.5 s | 4.2 s | 1.9 s | images, hosting, CDN |
| INP (interactivity) | < 200 ms | 340 ms | 150 ms | JavaScript, hydration |
| CLS (stability) | < 0.1 | 0.24 | 0.05 | media dimensions, fonts |
| Bounce rate | - | 58 % | 45 % | overall perceived speed |
| Average SERP position | - | 14 | 8 | all signals combined |
The three metrics are linked: cutting image weight improves LCP, trimming JavaScript improves INP, and setting block dimensions fixes CLS.
What the budget and maintenance cover
Price depends on site size, CMS and technical debt. The table below breaks down a typical project over 3 to 5 weeks.
| Line item | Small site (3,500-5,000 EUR) | Medium site (5,500-7,000 EUR) | Complex site (7,500-9,000 EUR) |
|---|---|---|---|
| Audit + diagnosis (CrUX field data) | 800-1,000 EUR | 1,000-1,300 EUR | 1,300-1,600 EUR |
| WebP/AVIF image optimization | 600-900 EUR | 900-1,200 EUR | 1,200-1,600 EUR |
| JS/CSS loading rework | 900-1,400 EUR | 1,400-2,000 EUR | 2,000-2,800 EUR |
| CDN + hosting config | 500-800 EUR | 800-1,200 EUR | 1,200-1,600 EUR |
| Testing + report delivery | 700-900 EUR | 1,300-1,400 EUR | 1,800-2,400 EUR |
| Monthly performance maintenance | 300 EUR | 450 EUR | 600 EUR |
Maintenance prevents regression: every new campaign, marketing tag or plugin can degrade the metrics if no one watches the performance budget.
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Mini case study
Sophie, marketing lead at an industrial mid-cap in Berlin, sees organic traffic stall despite good content. The audit reveals a 4.2 s LCP caused by uncompressed images and a saturated shared host. The project, quoted at 6,200 EUR HT over 4 weeks, brings LCP to 1.9 s and INP to 150 ms. Result over three months: bounce rate from 58 % to 45 %, average position from 14 to 8, and +31 % organic sessions. With a site generating 40 leads/month at an average value of 900 EUR, that +31 % is about 12 extra leads/month, i.e. 10,800 EUR of additional monthly pipeline: the audit pays for itself in under a month of effect.
FAQ
How long does a CWV audit take? The diagnosis alone takes 3 to 5 days; the audit with full optimization runs over 3 to 5 weeks depending on site size and accumulated technical debt.
Is lab data enough? No. Google ranks on field data (CrUX, real users). A good audit cross-references Lighthouse (lab) and field data to prioritize what truly matters for ranking.
Does a fast site guarantee better positions? Speed is one signal among several, but a slow site is penalized and drives visitors away. Fixing CWV unlocks the potential of content already in place.
Do we need a full site rebuild? Rarely. Most gains come from image optimization, JavaScript loading and a good CDN, with no full visual redesign.
Why monthly maintenance? Because metrics regress: new marketing scripts, unoptimized images, CMS updates. A budget of 300 to 600 EUR/month keeps thresholds in the green.
Let's scope your project. Send us the URL, the CMS and your current CWV scores; we frame an audit between 3,500 and 9,000 EUR HT by complexity. 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.
