The verdict in three sentences
Migrating a London B2B website to multilingual EN/FR/ES is first an SEO and technical project, not a simple translation job. A realistic 2026 budget runs from 10,000 to 25,000 EUR ex. VAT depending on content volume, with professional translation at 0.10-0.18 EUR/word as the main variable cost. The number-one risk is not cost but a traffic loss of 15-40 % when 301 redirects and hreflang are done carelessly.
The budget line by line (2026 ballpark)
An export director wants firm numbers before committing. Here is the typical breakdown for a 30-to-50-page B2B showcase site, roughly 20,000 words to translate.
| Item | 2026 range (EUR ex. VAT) | Note |
|---|---|---|
| Audit + hreflang strategy | 1,500 - 3,000 | URL mapping, redirect plan |
| Technical migration | 6,000 - 14,000 | i18n rebuild, routing, multilingual CMS |
| Pro translation (20,000 words) | 2,000 - 3,600 | 0.10-0.18 EUR/word, FR + ES |
| Proofreading / linguistic QA | 800 - 1,500 | Native review per language |
| SEO acceptance + monitoring | 1,000 - 2,500 | 90-day post-migration tracking |
| Project total | 11,300 - 24,600 | Excludes recurring maintenance |
On top of that, budget 300-600 EUR/month of multilingual maintenance: content updates, keeping three languages in sync, hreflang fixes as new pages ship.
URL architecture: the choice that locks in your SEO
The multilingual structure drives the whole migration budget and traffic recovery. The three common options are not equal.
| Structure | Example | Relative cost | SEO / authority |
|---|---|---|---|
| Subdirectories | site.com/fr/ | Cheapest | Shared authority, recommended |
| Subdomains | fr.site.com | Medium | Fragmented authority |
| ccTLD | site.es | Most expensive | Strong geo-targeting, heavy to run |
| URL parameter | site.com/?lang=es | Low | Avoid, poor crawling |
For a B2B site going international for the first time, subdirectories with hreflang offer the best cost/performance ratio: the root domain's authority benefits every language, and migration stays contained around 6,000-14,000 EUR ex. VAT.
Mini case study
Thomas, export director of an industrial SME in London (technical supplies), wants to open Spain and France. His site has 40 pages, 22,000 words. Accepted quote: audit 2,200 EUR, technical migration 9,500 EUR, translation 22,000 words x 0.14 EUR = 3,080 EUR, QA 1,200 EUR, SEO acceptance 1,800 EUR, i.e. 17,780 EUR ex. VAT. He adds maintenance at 450 EUR/month. Target: 15 extra international leads per year. With an average project value of 8,000 EUR and a lead-to-client conversion of 20 %, that is 24,000 EUR of additional annual revenue — the project pays for itself in year one, maintenance included.
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FAQ
How long does a multilingual B2B migration take?
Expect 8 to 14 weeks: 2-3 weeks of audit and strategy, 4-6 weeks of development, 2-3 weeks of translation/QA in parallel, then acceptance and monitoring. Projects that slip are those where translation starts too late.
Will I lose my existing SEO traffic?
A poorly managed migration causes 15-40 % traffic loss over 1-3 months. With a thorough 301 redirect plan, correct hreflang and monitoring, the loss is limited to a few transient percent, usually recovered within 6-10 weeks.
Is machine translation enough?
No for B2B: raw machine translation produces technical mistranslations that destroy credibility. The MTPE model (human post-editing) cuts cost to 0.06-0.09 EUR/word while keeping acceptable quality for secondary pages.
Should I translate the whole site at once?
No. Prioritise lead-generating pages (offers, case studies, contact) and strong SEO content. The blog and side pages can follow in batches, spreading translation spend.
What hosting for an international site?
European hosting with a CDN is enough for EN/FR/ES targeting Europe. Budget 50-150 EUR/month for a fast B2B showcase site, with response times under 200 ms from Paris and Madrid.
Let's scope your project. Tell us about your current site (page count, words, target languages) and your deadline: we will price audit, migration and translation in a 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.
