The verdict in three sentences
A B2B site that loads in 4.8 seconds loses Google rankings and converts poorly, because Core Web Vitals are a confirmed ranking signal. In 2026, budget EUR 900-1,800 for a scoped diagnostic and EUR 2,500-6,000 for a full optimization project (AVIF images, lazy-load, caching, TTFB). The goal is measurable: LCP < 2.5 s, INP < 200 ms, CLS < 0.1, with an expected ROI of +15 to +30% conversion.
What Core Web Vitals actually measure
Since March 2024, INP (Interaction to Next Paint) replaced FID and measures the real responsiveness of every click. Three metrics now matter for SEO and UX: LCP (main content render speed), INP (responsiveness), and CLS (visual stability). A typical B2B site (poorly configured WordPress or headless) usually fails LCP due to uncompressed images and an excessive server TTFB.
| Metric | Good (2026) | Needs work | Poor | Common cause |
|---|---|---|---|---|
| LCP | < 2.5 s | 2.5-4 s | > 4 s | Heavy images, high TTFB |
| INP | < 200 ms | 200-500 ms | > 500 ms | Blocking JavaScript |
| CLS | < 0.1 | 0.1-0.25 | > 0.25 | Images without dimensions, ads |
| TTFB | < 0.8 s | 0.8-1.8 s | > 1.8 s | Shared hosting, no cache |
| Page weight | < 1.5 MB | 1.5-3 MB | > 3 MB | No AVIF/WebP |
2026 pricing breakdown (EUR, ex. VAT)
The budget splits into two stages: first a diagnostic that prioritizes levers by impact/effort, then the implementation project. The figures below reflect the 2026 market for qualified agencies and freelancers.
| Service | 2026 price (EUR ex. VAT) | Timeline | Deliverable |
|---|---|---|---|
| Diagnostic + action plan | 900 - 1,800 | 3-5 days | Prioritized report, scoped budget |
| Image optimization (AVIF/WebP, srcset) | 600 - 1,500 | 1 week | Automated image pipeline |
| Lazy-load + code splitting | 800 - 2,000 | 1-2 weeks | Deferred JS, smaller bundles |
| Cache + CDN + TTFB | 700 - 1,800 | 1 week | Server cache, edge caching |
| Full project | 2,500 - 6,000 | 3-5 weeks | Guaranteed LCP < 2.5 s |
Optimized hosting or a CDN typically adds EUR 40-120/month depending on traffic.
Mini case study
Thomas, marketing director of an industrial SME in Nantes, runs a site with 45,000 visits/month and a 4.6 s LCP. After a project billed at EUR 4,200, the LCP drops to 2.1 s and the quote-form conversion rate rises from 1.3% to 1.7%, i.e. +180 qualified leads/year. At an average value of EUR 320 per lead, the annual gain exceeds EUR 57,000: the investment pays back in under 30 days, before counting the SEO ranking gains on competitive queries.
FAQ
Need a professional website?
Kolonell builds websites that attract clients, optimized for the Sénégalese market. Free quote in 2 minutes.
How long does a Core Web Vitals optimization take?
Expect 3 to 5 weeks for a full project, including diagnostic, implementation, and field verification (CrUX data). The first gains are measurable from week two.
Do Core Web Vitals really affect SEO in 2026?
Yes. They are part of Google's page experience signals. With equal content, a site that passes the "good" threshold on all three metrics gains rankings, especially on mobile where 60% of B2B traffic happens.
Can you guarantee an LCP < 2.5 s?
A serious provider guarantees the threshold on strategic pages (home, landing, product). Third-party pages (embedded forms, chat) sometimes depend on external scripts we optimize but do not fully control.
What ROI can I realistically expect?
2026 data puts the conversion gain between 15 and 30% depending on the starting state. Every 100 ms of LCP saved is worth roughly +1% conversion on a B2B funnel.
Should I rebuild the site or just optimize it?
In 80% of cases, optimization is enough. A rebuild is only justified if the architecture (bloated theme, heavy page builder) makes the gains impossible to sustain over time.
Let's scope your project. Send us your URL and current PageSpeed scores; we will scope a Core Web Vitals plan (diagnostic EUR 900-1,800, project EUR 2,500-6,000) matched to your traffic. 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.
