The verdict in three sentences
An industrial website that loads in 6 seconds on mobile drives away part of your buyers before they even see your catalog. In most cases, a targeted optimization at 3,000 to 6,000 EUR, preceded by an audit at 900 to 1,800 EUR, is enough to bring LCP under 2.5 s and INP under 200 ms. A redesign at 12,000 EUR or more is only justified if the audit reveals an outdated CMS or an architecture that cannot be fixed.
Core Web Vitals in decision-maker language
Google measures your visitors' real experience with three metrics taken from Chrome browsing data (the CrUX report). They influence rankings and, above all, conversion.
| Metric | What it measures | « Good » threshold | Typical value on a slow industrial site |
|---|---|---|---|
| LCP (Largest Contentful Paint) | Time to display the largest visible element | Under 2.5 s | 5 to 7 s on mobile 4G |
| INP (Interaction to Next Paint) | Responsiveness to clicks, filters, menus | Under 200 ms | 350 to 600 ms |
| CLS (Cumulative Layout Shift) | Visual stability while loading | Under 0.1 | 0.2 to 0.4 |
| Home page weight | Data downloaded | Under 2 MB | 6 to 12 MB (videos, PDFs, uncompressed images) |
| Third-party scripts | Chat, tracking, maps, widgets | Fewer than 5 | 10 to 20 |
The most common causes on an equipment maker's site: an uncompressed demo video on the home page, product pages loading 20 high-definition photos at once, a heavy JavaScript configurator, and a pile of marketing tags never cleaned up.
Audit, optimization or redesign: comparing the three options
The figures below are 2026 market estimates from our European benchmark (Lyon); New York agencies quote comparable ranges in USD, often at the higher end.
| Option | Cost excl. tax (2026 estimate) | Timeline | When to choose it |
|---|---|---|---|
| Core Web Vitals audit | 900 to 1,800 EUR | 1 to 2 weeks | Always first, to price the rest |
| Targeted optimization | 3,000 to 6,000 EUR | 3 to 6 weeks | Up-to-date CMS, issues concentrated in images, scripts, cache |
| Optimization + hosting change | 4,500 to 8,000 EUR | 4 to 7 weeks | Saturated shared server, TTFB above 800 ms |
| Partial redesign (key templates) | 8,000 to 12,000 EUR | 6 to 10 weeks | Heavy theme but reusable content |
| Full redesign | 12,000 EUR and up | 3 to 5 months | End-of-life CMS, massive technical debt |
| Monthly performance monitoring | 150 to 400 EUR/month | Ongoing | Avoid relapse after each content addition |
The audit acts as a filter. A good audit delivers a prioritized list, for example « switch images to AVIF and WebP: estimated 1.8 s LCP gain », « defer live chat: estimated 150 ms INP gain ». With that list, you compare each fix's cost directly with the expected gain.
The business gain: what public studies say
Several studies published by Google and by e-commerce and B2B players report conversion increases of 8 to 15% after a clear improvement in load times. For an industrial site, conversion means quote requests, technical sheet downloads and sales contacts.
| Metric tracked | Before optimization (example) | Target after optimization |
|---|---|---|
| Mobile LCP | 6.0 s | 2.2 s |
| Mobile bounce rate | 68% | 50 to 55% |
| Pages per visit | 1.9 | 2.5 to 3 |
| Quote request rate | 1.2% | 1.3 to 1.4% (+8 to +15%) |
| Share of « good » URLs in Search Console | 15% | 85% and above |
Note: Google ranking gains are real but modest. The real benefit is on conversion and on paid campaigns, where a fast site improves quality score and lowers cost per click.
Mini case study
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Tom, communications manager at a hypothetical equipment maker near New York, gets 9,000 visits a month with a 1.2% quote request rate, or 108 requests. The company closes one request in ten, with an average margin of 6,000 EUR per deal.
He orders an audit at 1,400 EUR then an optimization at 4,500 EUR, 5,900 EUR in total. If conversion rises 10%, he gets about 11 more requests a month, so roughly one extra signed deal, or 6,000 EUR of monthly margin. The investment pays back in about a month, whereas a 12,000 EUR redesign would have taken two more months for a comparable speed result.
FAQ
Does a slow site really hurt SEO?
Core Web Vitals are ranking signals, but their weight stays limited compared with content relevance. The strongest impact is on conversion, with 8 to 15% increases observed in public studies.
How much does a serious Core Web Vitals audit cost?
Between 900 and 1,800 EUR in 2026 depending on the number of templates analysed. It must include field data (CrUX), a costed action plan and an estimated gain per fix.
Can we optimize without changing CMS?
In about two cases out of three, yes. If the CMS is up to date and the problem comes from images, third-party scripts and caching, a 3,000 to 6,000 EUR optimization is enough.
How fast do results show in Google?
Lab measurements improve immediately. Search Console field data updates over a rolling 28-day window, so allow 4 to 6 weeks.
How do we stop the site slowing down again?
Set a performance budget (maximum page weight, number of scripts) and a monthly check. Monitoring at 150 to 400 EUR a month costs far less than another optimization project.
Let's scope your project. Send us your site URL and conversion goals and we will tell you whether to optimize or redesign, with a costed budget and timeline. 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.
