The verdict in three sentences
When a B2B site has good content but slides down Google, the culprit is almost always technical performance: a Lighthouse score of 42 and a 4.5 s LCP hurt both ranking and conversion. A Core Web Vitals audit at 1,500-3,000 EUR targets LCP < 2.5 s, INP < 200 ms and CLS < 0.1, and lifts the score to 90+. The return is measurable: +12 % form conversions and +9 % page views for every 0.8 s of LCP saved.
The three metrics that decide ranking
Core Web Vitals are a confirmed Google ranking signal. In 2026, three metrics matter, each with a precise threshold.
| Metric | What it measures | Good (2026) | Needs work | Poor |
|---|---|---|---|---|
| LCP (Largest Contentful Paint) | Main content display speed | < 2.5 s | 2.5-4 s | > 4 s |
| INP (Interaction to Next Paint) | Click responsiveness | < 200 ms | 200-500 ms | > 500 ms |
| CLS (Cumulative Layout Shift) | Visual stability | < 0.1 | 0.1-0.25 | > 0.25 |
| Overall Lighthouse score | Performance summary | 90-100 | 50-89 | < 50 |
| TTFB (server) | Server response time | < 800 ms | 0.8-1.8 s | > 1.8 s |
A site failing all three is doubly penalized: Google demotes it, and the user leaves before even seeing the offer.
Optimize the existing site or migrate: the comparison
The marketing lead of a mid-cap has two paths. Optimize the current WordPress, or migrate to a modern stack such as Next.js. The choice depends on technical health and SEO ambition.
| Criterion | WordPress optimization | Next.js migration |
|---|---|---|
| Budget 2026 | 4,000-6,000 EUR | 15,000-20,000 EUR |
| Timeline | 2-4 weeks | 6-10 weeks |
| Target Lighthouse score | 42 → 78-85 | 42 → 92-98 |
| Expected LCP | ~2.4 s | ~1.3 s |
| Estimated SEO gain (20 keywords) | +4 to +8 positions | +8 to +15 positions |
| Durability | Medium (technical debt) | High |
| Maintenance cost | Moderate | Low |
For a high-traffic, high-stakes site, migration pays off; for a decent site that has just drifted, targeted optimization is often enough.
Need a professional website?
Kolonell builds websites that attract clients, optimized for the Sénégalese market. Free quote in 2 minutes.
Mini case study
Sophie, marketing lead at a 180-person industrial mid-cap, sees her site drop from page 1 to page 3 on its 20 strategic keywords despite good content. Audit: LCP at 4.6 s, CLS at 0.31, Lighthouse score 42.
She invests 5,200 EUR in a WordPress optimization (AVIF images, lazy loading, server cache, optimized fonts). In 6 weeks, the score reaches 84 and LCP drops to 2.3 s. Over 3 months: +12 % form conversions, +9 % page views, and 11 keywords back on page 1. With 40 leads/month worth 800 EUR average, the conversion gain covers the investment in under 2 months.
FAQ
Do Core Web Vitals really affect Google ranking? Yes, it is a confirmed signal, especially at equal content quality. Between two comparable pages, the one loading in 1.3 s outranks the one loading in 4 s, and the gap widens on mobile.
Do I have to migrate to Next.js? No. A well-run WordPress optimization lifts a score from 42 to 80+ for 4,000-6,000 EUR. The 15,000-20,000 EUR migration is justified for high traffic, a 95+ score requirement or heavy technical debt.
What is speed's impact on conversions? Every 0.8 s of LCP saved is worth about +9 % page views, and the full optimization delivered +12 % form conversions in our case. Performance is as much a commercial lever as an SEO one.
How much does a Core Web Vitals audit alone cost? Expect 1,500-3,000 EUR for a full audit with a prioritized action plan. It includes Lighthouse tests, field data (CrUX) analysis and a costed roadmap.
How long to see the SEO effect after optimization? Metrics improve immediately, but Google takes 4 to 8 weeks to re-evaluate positions. On a high-traffic site, the first ranking gains often appear by week 5.
Let's scope your project. Send us your URL and your 20 priority keywords: we will price an audit, optimization or migration with estimated SEO gain and an indicative budget. 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.
