The verdict in three sentences
A Core Web Vitals audit of a B2B site costs, in 2026, between 1,200 and 2,500 EUR, and the optimizations that follow between 3,000 and 7,000 EUR depending on technical debt. The measured gains are concrete: LCP from 3.8 s to 1.2 s, INP under 200 ms, improved crawl budget and +10 to 24% conversion. Prioritize fixes by impact: every conversion point gained pays for itself within weeks on a commercial site.
What the audit covers and its cost
2026 Core Web Vitals rest on three metrics: LCP (largest element loading), INP (interaction responsiveness, which replaced FID) and CLS (visual stability). A serious audit measures them in the lab and with field data (CrUX).
| Audit item | 2026 cost (EUR) | What is analyzed |
|---|---|---|
| Express audit (1 template) | 1,200 - 1,500 | LCP, INP, CLS + 10 recommendations |
| Full multi-template audit | 1,800 - 2,500 | Home, listing, product, form, blog |
| Crawl budget analysis | +400 - 700 | Server logs, crawl budget |
| Competitive benchmark | +300 - 500 | 3 competitors compared |
| Post-fix tracking | 350 / mo | CrUX monitoring + alerts |
The report is only as good as its roadmap: every issue must be costed in hours and ranked by business impact.
Optimization costs and expected gains
| Optimization | 2026 cost (EUR) | Typical gain | Target metric |
|---|---|---|---|
| WebP/AVIF image compression | 600 - 1,200 | -40 to 60% weight | LCP |
| Lazy loading + preload | 400 - 900 | -0.5 to 1.2 s | LCP |
| Cache + CDN | 800 - 1,800 | -30 to 50% TTFB | LCP, INP |
| Code splitting + JS defer | 1,000 - 2,500 | -100 to 300 ms | INP |
| Space reservation (CLS) | 400 - 800 | CLS < 0.1 | CLS |
| Font optimization | 300 - 600 | -0.2 to 0.5 s | LCP |
Combined, a 5,000 EUR project typically moves a site from "needs improvement" to "good" on all three metrics, with LCP cut by three.
ROI and prioritization
The golden rule: fix what has the highest impact/cost ratio first. On a B2B site generating quote requests, a 1-second LCP improvement lifts conversion by roughly 7 to 12%.
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| Priority | Action | Impact/cost ratio | Timeline |
|---|---|---|---|
| 1 | Images + fonts | Very high | 3 - 5 days |
| 2 | Cache + CDN | High | 4 - 7 days |
| 3 | JS defer / splitting | Medium-high | 5 - 10 days |
| 4 | Heavy component rebuild | Medium | 10 - 20 days |
Mini case study
Thomas is head of e-marketing at a software vendor in Nantes. His site converts at 2.1% and generates 400 quote requests/month. He invests 2,000 EUR in audit + 5,000 EUR in optimizations. LCP falls from 3.8 s to 1.3 s and conversion climbs to 2.5%, a +19% lift. That means 76 extra requests per month; at an 8% close rate and a 4,500 EUR average deal, it adds about 27,000 EUR in monthly revenue. The 7,000 EUR invested is recouped in under a month.
FAQ
Did INP really replace FID? Yes, since March 2024 INP is the official responsiveness metric. Aim under 200 ms; beyond 500 ms, Google rates the experience poor.
Does a good Core Web Vitals score lift rankings? It is one ranking factor among many, but above all a strong conversion lever. The SEO effect is real on competitive queries with equivalent content.
How long do the optimizations take? Expect 2 to 4 weeks for a full 5,000 EUR project, excluding heavy component rebuilds. Image/font gains land within the first week.
Should I re-audit after fixes? Yes, a post-fix check (350 EUR/month monitoring) validates gains on CrUX field data, which refreshes over a rolling 28 days.
Mobile or desktop first? Mobile first: Google indexes mobile-first and B2B mobile traffic often exceeds 45%. Thresholds are harder to hold on mobile.
Let's scope your project. Send us the URL to audit, your CMS and your current conversion rate: we will cost the audit and the priority fixes. 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.
