The verdict in three sentences
Core Web Vitals (LCP, INP, CLS) are now both a Google ranking factor and a direct conversion driver: a slow B2B marketing site loses traffic and leads at once. In 2026, a performance audit costs 800 to 2,500 EUR and a full optimization 2,000 to 8,000 EUR depending on scope. Done right, optimization pushes LCP below 2.5s, INP below 200ms, CLS below 0.1, and routinely yields +18% conversions.
Understanding the three metrics and their thresholds
Google scores each metric on three tiers: good, needs improvement, poor. A typical B2B marketing site often exceeds the thresholds on mobile, exactly where B2B traffic matters.
| Metric | "Good" threshold | "Poor" threshold | What it measures | Common cause |
|---|---|---|---|---|
| LCP | < 2.5s | > 4.0s | Main content load | Unoptimized images, slow hosting |
| INP | < 200ms | > 500ms | Interaction responsiveness | Excess JavaScript, long tasks |
| CLS | < 0.1 | > 0.25 | Visual stability | Images without dimensions, fonts |
| TTFB | < 800ms | > 1,800ms | Server response | Saturated shared hosting |
| FCP | < 1.8s | > 3.0s | First paint | Render-blocking CSS |
Before / after: what an optimization project changes
Here are typical 2026 gains on a WordPress or Next.js B2B marketing site after a 4,000-6,000 EUR optimization.
| Indicator | Before | After | Main lever |
|---|---|---|---|
| Mobile LCP | 4.2s | 2.1s | WebP images + CDN + lazy load |
| INP | 420ms | 160ms | JS reduction + code splitting |
| CLS | 0.28 | 0.04 | Media dimensions + fonts |
| TTFB | 1,600ms | 520ms | Server cache + hosting |
| Mobile PageSpeed score | 42 / 100 | 91 / 100 | All optimizations combined |
| Conversion rate | 1.8% | 2.1% | +18% relative |
Mini case study
Sophie is head of digital at a B2B industrial firm whose marketing site gets 12,000 visits/month and converts at 1.8%, i.e. 216 quote requests monthly. She commissions a Core Web Vitals optimization at 5,500 EUR. Afterward, the conversion rate rises to 2.1%, i.e. 252 requests/month, or 36 extra leads. With a 10% close rate and a 4,200 EUR average deal, that is 15,120 EUR of additional monthly revenue: the investment pays back in under two weeks of gains.
Need a professional website?
Kolonell builds websites that attract clients, optimized for the Sénégalese market. Free quote in 2 minutes.
FAQ
Do I need to rebuild the whole site to fix Core Web Vitals?
Rarely. In 70% of cases, targeted optimization (images, cache, JavaScript, hosting) is enough. A full rebuild is only needed if the technical foundation is obsolete, and then costs 8,000 EUR and up.
How long does an optimization take?
Between 2 and 5 weeks depending on complexity: one week of audit, then 1 to 4 weeks of implementation and testing. Gains appear in Search Console within 28 days after going live.
Does CLS really have a business impact?
Yes: content that jumps during load makes visitors click the wrong element and raises bounce rate. Moving CLS from 0.28 to under 0.1 measurably improves engagement.
Is my shared hosting a problem?
Often, yes: a TTFB above 1,500ms drags down LCP no matter what you do on the front end. Migrating to fast hosting or a CDN is one of the first levers, at 25 to 75 EUR/month.
Let's scope your project. Send us your site URL and current PageSpeed scores, and we'll price an audit plus a prioritized optimization plan. 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.
