The verdict in three sentences
A B2B site with an LCP of 4.8 s and an INP of 450 ms on mobile fails Google's thresholds and loses a measurable share of visitors before the page even renders. In about 70% of cases, an audit at EUR 2,000 to 5,000 followed by targeted fixes at EUR 4,000 to 15,000 is enough to get back to green. A full technical rebuild (EUR 20,000 to 50,000) is only justified when the CMS or theme structurally blocks performance.
Where your site stands against 2026 thresholds
Google scores three metrics on real Chrome user data (the CrUX report), at the 75th percentile. A typical mid-sized B2B site with a product catalogue, videos and marketing tags often sits in the right-hand column.
| Metric | Good | Needs improvement | Poor | Typical B2B site (mobile) |
|---|---|---|---|---|
| LCP (main content render) | under 2.5 s | 2.5 to 4 s | over 4 s | 4.8 s |
| INP (click responsiveness) | under 200 ms | 200 to 500 ms | over 500 ms | 450 ms |
| CLS (visual stability) | under 0.1 | 0.1 to 0.25 | over 0.25 | 0.18 |
| Average product page weight | under 1.5 MB | 1.5 to 3 MB | over 3 MB | 4.2 MB |
| Third-party scripts loaded | under 5 | 5 to 10 | over 10 | 14 |
| TTFB (server response) | under 0.8 s | 0.8 to 1.8 s | over 1.8 s | 1.4 s |
The causes are always the same: oversized JPEGs, a hero carousel, fonts loaded from Google Fonts, a tag manager stacking Hotjar, LinkedIn Insight, live chat and two analytics tools, and shared hosting without a CDN. Dutch sites add a heavy cookie consent banner, often itself a CLS and INP culprit.
Three levels of work and what they cost
| Level | Scope | 2026 cost (EUR, excl. VAT) | Timeline | Expected LCP gain |
|---|---|---|---|---|
| Audit only | CrUX and Lighthouse measurement, script map, prioritised plan | 2,000 to 5,000 | 1 to 2 weeks | 0, it is a diagnosis |
| Quick fixes | AVIF/WebP images, lazy loading, font preload, CDN | 4,000 to 7,500 | 2 to 3 weeks | 1 to 2 s |
| Deep fixes | Third-party cleanup, JavaScript splitting, server caching, critical rendering | 7,500 to 15,000 | 4 to 6 weeks | 2 to 3 s |
| Technical rebuild | Migration to a modern framework (Next.js, Astro) or new theme | 20,000 to 50,000 | 10 to 16 weeks | 3 s or more |
| Monthly monitoring | CrUX tracking, regression alerts, review of new scripts | 200 to 600 per month | Ongoing | Prevents relapse |
Amsterdam agency day rates sit around EUR 800 to 1,100 in 2026. A nearshore French-speaking agency typically delivers the same scope 30 to 50% cheaper. The common trap is fixing once, then letting marketing add three new ad pixels. Without monitoring, gains vanish within six months.
Estimate the payback before you sign
The rule of thumb used by e-commerce and B2B teams: each second of LCP saved cuts bounce rate by 10 to 20% on product pages. For a B2B firm, the metric that matters is quote requests, not visits. Start from your analytics: monthly mobile sessions on product pages, bounce rate, conversion to contact request, and average deal value.
SEO benefits too, more modestly: Core Web Vitals act as a tie-breaker between equally relevant pages. Speed alone will not get you to page one, but a slow site can drop off it against an equally relevant competitor.
Mini case study
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Sarah, marketing manager at a 350-person manufacturer of conveyor systems near Amsterdam, gets 9,000 mobile sessions a month on product pages, with 62% bounce and 0.8% conversion to quote request, or 72 requests. After an audit (EUR 3,500) and deep fixes (EUR 10,500), LCP drops from 4.8 s to 2.1 s. Assuming a conservative 25% bounce reduction, bounce falls to 46.5%, adding about 1,400 engaged sessions. Her 72 requests currently come from 3,420 engaged sessions, or 2.1%; at the same rate, she gains roughly 29 requests a month. With a 10% close rate and EUR 6,000 margin per deal, that is about 3 deals and EUR 18,000 of monthly margin: the EUR 14,000 investment pays back in under two months.
FAQ
How much does a Core Web Vitals audit cost for a B2B site?
Between EUR 2,000 and 5,000 in Amsterdam depending on the number of templates and technical complexity. The audit should deliver a prioritised plan with effort per fix, not just a Lighthouse score.
Do we need a new site to pass Core Web Vitals?
Rarely. In about 70% of cases, fixes at EUR 4,000 to 15,000 are enough. A rebuild makes sense when the CMS or page builder ships more than 2 MB of unused code per page.
How long before results show in Search Console?
CrUX data is calculated over a rolling 28 days. Expect 4 to 6 weeks after release to see URLs move to "good" in the Core Web Vitals report.
Is INP harder to fix than LCP?
Often yes, because it depends on JavaScript executed on click: menus, filters, third-party scripts. An INP of 450 ms usually drops under 200 ms once non-essential scripts are deferred and long tasks are split.
Is a CDN enough?
A CDN cuts TTFB by 30 to 60% for distant visitors, but it does not fix 800 KB images or bloated JavaScript. It is one building block among several.
Let's scope your project. Send us your site URL and your three most strategic pages, and we will estimate the level of work, budget and timeline to get back to green. 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.
