The verdict in three sentences
In 2026, Core Web Vitals optimisation for a B2B site in Amsterdam is priced at EUR 1,200 to 4,000 depending on the technical starting point. The goal is an LCP under 2.5s, an INP under 200ms and a CLS near zero, achievable in 1 to 3 weeks. Beyond SEO, every second saved on load time measurably improves the conversion rate: on a lead-generating site, the operation usually pays for itself within one or two months.
The technical items of a performance optimisation
Core Web Vitals do not improve through one magic setting but through a series of targeted actions: image compression and modern formats, server and browser caching, CDN deployment, JavaScript trimming, deferred loading and font optimisation.
| Technical item | Main impact | Order-of-magnitude cost |
|---|---|---|
| Images (WebP/AVIF, lazy load) | LCP | EUR 300-800 |
| Server + browser cache | LCP, TTFB | EUR 250-600 |
| CDN setup | LCP, latency | EUR 200-500 (+ sub) |
| JavaScript reduction | INP | EUR 400-1,200 |
| Visual stability (CLS) | CLS | EUR 200-500 |
| Fonts and rendering | LCP, CLS | EUR 150-400 |
| Total | EUR 1,200-4,000 |
A recent brochure site needs fewer interventions than an old site overloaded with plugins or marketing scripts.
Before/after scores and business impact
Here is a 2026 order of magnitude of typical gains on a moderately optimised B2B site.
| Metric | Before | After | Effect |
|---|---|---|---|
| LCP | 4.8s | 1.9s | -60% time |
| INP | 380ms | 150ms | Smooth responsiveness |
| CLS | 0.28 | 0.03 | No more visual jumps |
| Mobile PageSpeed score | 42 | 91 | Google threshold met |
| Bounce rate | 58% | 44% | -14 points |
| Conversion rate | 1.6% | 2.3% | +0.7 point |
Google uses Core Web Vitals as a ranking signal; moving into the green improves visibility while reducing bounce, a double benefit.
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Mini case study
Nathalie is marketing director at a B2B software vendor in Amsterdam. Her site draws 9,000 visits/month but converts at 1.5%, i.e. 135 leads. She invests EUR 2,800 in a Core Web Vitals optimisation over 2 weeks. The conversion rate rises to 2.2%, i.e. 198 leads/month, +63 leads. At an average value of EUR 90 per qualified lead, that is EUR 5,670 of extra value per month. The EUR 2,800 investment is recouped in under three weeks of traffic, and the gain compounds month after month with no recurring cost.
FAQ
How long does a Core Web Vitals optimisation take? Usually 1 to 3 weeks depending on the scope of fixes. Images and caching deliver quick wins; JavaScript reduction takes more work.
Do Core Web Vitals really influence Google ranking? Yes, they are part of Google's "page experience" signals. They do not replace content, but at equal content a fast, stable site ranks better and retains more visitors.
What LCP target should I aim for? An LCP under 2.5 seconds is considered "good" by Google. Between 2.5 and 4s it is "needs improvement", beyond 4s it is "poor" and penalising.
Do I need to rebuild the whole site? Rarely. Most gains come from targeted optimisations on an existing site. A full rebuild is only justified if the technical architecture is obsolete.
Is the conversion gain guaranteed? No serious provider guarantees a precise figure, but the correlation between speed and conversion is well documented. We measure before/after to make the return objective.
Let's scope your project. Slow B2B site in Amsterdam: send us your URL and traffic volume, and we will audit your Core Web Vitals and scope the optimisation (EUR 1,200-4,000). 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.
