The verdict in three sentences
Optimising Core Web Vitals during a redesign in Amsterdam costs in 2026 between EUR 2,500 and 7,000 in targeted work, cutting an LCP from 3.1 s to 1.2 s with an INP below 200 ms. The measured impact on B2B sites: +9 to +15 % organic traffic, -20 % bounce rate and +7 % conversion. For a high-traffic site, the investment pays back in 3 to 6 months.
What Core Web Vitals measure
Since 2021, Google factors three performance metrics into its ranking. In 2026, INP has definitively replaced FID and tightens interactivity requirements. Here are the thresholds to hit.
| Metric | Good | Needs work | Poor |
|---|---|---|---|
| LCP (loading) | < 2.5 s | 2.5 - 4 s | > 4 s |
| INP (interactivity) | < 200 ms | 200 - 500 ms | > 500 ms |
| CLS (visual stability) | < 0.1 | 0.1 - 0.25 | > 0.25 |
A typical unoptimised WordPress B2B site often shows LCP 3.1 s, INP 380 ms, CLS 0.18: three metrics in the red or amber, which caps rankings and drives mobile visitors away.
Cost and gain of optimisation
Core Web Vitals optimisation is priced by the scope of fixes: image compression, lazy loading, JavaScript reduction, caching, migration to a performant stack. Here is the 2026 grid.
| Scope | Cost | Typical LCP gain | Timeline |
|---|---|---|---|
| Quick wins (images, cache) | EUR 2,500 - 3,500 | 3.1 s to 1.8 s | 1 - 2 wks |
| Advanced optimisation (JS, fonts) | EUR 3,500 - 5,000 | 3.1 s to 1.4 s | 2 - 3 wks |
| Stack rebuild (Next.js) | EUR 5,000 - 7,000 | 3.1 s to 1.0 s | 3 - 5 wks |
The return is twofold: SEO gain (Google favours fast pages) and conversion gain (each second of load time removed improves the conversion rate by 3 to 7 %).
Mini case study
Sophie, marketing director of a B2B software vendor in Amsterdam, runs a site at 40,000 visits/month, LCP 3.1 s, conversion rate 2.0 %. She invests EUR 5,500 in advanced optimisation: LCP drops to 1.2 s, INP to 170 ms. Result over 4 months: +12 % organic traffic (44,800 visits) and +7 % conversion (2.14 %). That means roughly 160 extra monthly leads. At an average value of EUR 40 per lead, the monthly gain reaches EUR 6,400. The investment pays back in under a month of additional gain.
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FAQ
How much does Core Web Vitals optimisation cost?
Between EUR 2,500 and 7,000 in 2026 depending on scope. Quick wins at EUR 2,500-3,500 are often enough to turn all indicators green on a mid-sized site.
What SEO gain can I expect?
From +9 to +15 % organic traffic over 3 to 6 months for a site moving from red to green. Performance is not the only factor, but it unlocks an invisible ceiling on rankings.
Do I have to rebuild the whole site?
No. Many gains come from targeted fixes (images, JavaScript, cache) without a full rebuild. A stack rebuild is only worthwhile if the existing site is structurally slow.
What is INP and why does it matter in 2026?
INP measures responsiveness to user interactions; it has replaced FID. An INP below 200 ms is now required for good ranking, especially on mobile.
How long until the investment pays back?
From 3 to 6 months for a high-traffic site. For a site at 40,000 visits/month, the conversion gain often covers the cost in under a month.
Let's scope your project. Send us your URL and current PageSpeed scores: we price an optimisation plan and an indicative budget between EUR 2,500 and 7,000. 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.
