The verdict in three sentences
Optimizing the Core Web Vitals of a B2B site in Montreal costs, in 2026, between EUR 3,500 (audit + quick wins) and EUR 15,000 (full technical rebuild). The return shows on two axes: conversion (every second of LCP gained is worth several points of conversion rate) and SEO (CWV are a Google ranking signal). The best cost/impact ratio almost always comes from images, JavaScript and hosting, not a full rewrite.
What Google measures and where it breaks
In 2026, the three key metrics remain LCP (largest element load), INP (interaction responsiveness, which replaced FID) and CLS (visual stability). An average B2B site fails at least one of the three.
| Metric | "Good" threshold 2026 | Common failure cause |
|---|---|---|
| LCP | < 2.5 s | Heavy images, slow hosting, no cache |
| INP | < 200 ms | Excessive JavaScript, third-party scripts |
| CLS | < 0.1 | Images without dimensions, ads, fonts |
| TTFB | < 0.8 s | Unoptimized server, no CDN |
A typical diagnosis reveals that 60 to 70% of page weight comes from unoptimized images and third-party scripts (chat, analytics, pixels).
Budget, timelines and measured gains
The good news: most gains come from quick levers. Here are the 2026 tiers in Montreal.
| Service | Cost (EUR) | Timeline | Typical LCP gain |
|---|---|---|---|
| CWV technical audit | 800 - 1,800 | 3-5 days | Diagnosis only |
| Quick wins (images, cache, CDN) | 2,500 - 5,000 | 1-2 wk | -30 to -50% |
| JS refactor + lazy loading | 4,000 - 8,000 | 2-4 wk | -20 to -40% INP |
| Full technical rebuild | 9,000 - 15,000 | 4-8 wk | LCP < 1.8 s guaranteed |
| Monthly monitoring | 150 - 400/mo | ongoing | Score maintenance |
Common before/after example: LCP from 4.2s to 1.8s, mobile PageSpeed score from 38 to 89, conversion rate +8 to +15%.
Need a professional website?
Kolonell builds websites that attract clients, optimized for the Sénégalese market. Free quote in 2 minutes.
Mini case study
Sophie, B2B e-commerce lead at an equipment distributor in Montreal, sees a 62% mobile bounce rate and a 4.5s LCP. She invests EUR 4,200 in quick wins (WebP image compression, CDN, server cache, removal of 2 third-party scripts).
Result in 3 weeks: LCP at 1.9s, mobile bounce at 44%, conversions +11%. On monthly online revenue of EUR 90,000, those 11% represent about EUR 9,900 of additional monthly revenue: the project pays back in under two weeks of traffic.
FAQ
How much does a simple Core Web Vitals audit cost? Between EUR 800 and 1,800 in 2026 for a full technical audit with a prioritized action plan. It's the recommended starting point before any rebuild budget, to target high-impact levers.
Do Core Web Vitals really affect SEO? Yes, they are part of Google's page experience signals. All else equal, a fast site ranks better on competitive queries; observed organic traffic gains are often 5 to 20% within a few months.
How long to see results? Conversion gains are immediate at go-live. SEO impact takes 4 to 12 weeks to stabilize while Google re-collects field data (CrUX).
Do I need to rebuild the whole site? Rarely. In 70% of cases, a quick-wins budget of EUR 2,500 to 5,000 (images, cache, CDN, JS cleanup) is enough to hit the green zone. A full rebuild is only justified on an obsolete technical stack.
What conversion gain should I expect? 2026 order of magnitude: +8 to +15% conversion by dropping below 2s LCP on mobile. Every second gained on mobile weighs heavily on high-value B2B carts.
Let's scope your project. Send us your URL and current PageSpeed scores, and we'll identify the 3 priority levers 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.
