The verdict in three sentences
A B2B site that takes more than 3 seconds to render loses prospects before the first click: Core Web Vitals (LCP, INP, CLS) are now a measurable conversion lever. In 2026, an optimization project costs between USD 2,800 and 6,800 and delivers 8 to 20 % more conversions per point of speed gained. With a quote-request funnel, the return on investment often materializes in under three months.
The 2026 thresholds to target
Google evaluates three primary metrics. Moving from red to green improves both search ranking (SEO signal) and conversion rate (perceived experience).
| Metric | Good | Needs work | Poor | What it measures |
|---|---|---|---|---|
| LCP | < 2.5 s | 2.5-4 s | > 4 s | Main content render speed |
| INP | < 200 ms | 200-500 ms | > 500 ms | Interaction responsiveness |
| CLS | < 0.1 | 0.1-0.25 | > 0.25 | Visual stability |
| TTFB | < 0.8 s | 0.8-1.8 s | > 1.8 s | Server response time |
| Page weight | < 1.5 MB | 1.5-3 MB | > 3 MB | Downloaded volume |
Before / after: the impact on leads
Here is a typical case for a New York B2B lead-generation site, 18,000 visits/month, before and after a USD 4,600 performance project.
| Indicator | Before | After | Change |
|---|---|---|---|
| LCP | 4.1 s | 2.2 s | -46 % |
| INP | 380 ms | 160 ms | -58 % |
| CLS | 0.22 | 0.05 | -77 % |
| Bounce rate | 61 % | 44 % | -17 pts |
| Conversion rate | 1.8 % | 2.7 % | +50 % |
| Leads / month | 62 | 92 | +30 leads |
| Average SEO position | 14.2 | 9.6 | +4.6 ranks |
Mini case study
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Thomas, digital lead at a B2B software vendor in New York, sees a 61 % bounce rate and declining leads. Chosen project: image optimization (AVIF/WebP), lazy-loading, JavaScript reduction, CDN caching and optimized hosting, for USD 4,600. Result: +30 qualified leads/month. With an average value of USD 1,600 per closed lead and a 6 % close rate, that is roughly +2.6 deals/month, an ROI reached by week 6.
FAQ
How much does a Core Web Vitals project cost in 2026? Between USD 2,800 for a brochure site and USD 6,800 for a complex B2B site with many third-party scripts. Price depends mostly on the number of templates and technical debt (heavy theme, plugins, trackers).
How fast do conversions improve? The technical effect is immediate after launch. The SEO effect (better rankings) appears over 4 to 8 weeks, as Google re-crawls and progressively re-evaluates pages.
Is a PageSpeed score of 100 required? No. The goal is green on the three field-measured Core Web Vitals (CrUX data), not the lab score. Targeting 90+ on mobile is a good cost/benefit balance.
Is the problem hosting or code? Often both: a TTFB > 1.8 s points to hosting, an INP > 500 ms points to JavaScript. An audit separates the two and prioritizes high-impact fixes.
Do we need a full redesign for these gains? Not always. 60 to 70 % of gains come from no-redesign optimizations (images, cache, scripts). If the technical base is too heavy (old bloated theme), a headless migration becomes more cost-effective.
Let's scope your project. Send us your URL and traffic volumes: we'll audit your Core Web Vitals and quantify the expected conversion gain. 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.
