The verdict in three sentences
After acquiring a competitor, merging two websites totalling 450 pages in Amsterdam costs 30,000 to 55,000 EUR for a single brand and 35,000 to 75,000 EUR for a brand architecture. The real risk is not the budget but losing 15 to 35% of organic traffic if URLs are not mapped one by one. A temporary coexistence of 6 to 12 months is often the best call while the acquired brand still brings in its own orders.
Three scenarios, three budgets
The right scenario depends first on how well customers know the acquired brand, then on how much the offers overlap.
| Scenario | 2026 budget Amsterdam (ex. VAT) | Timeline | Traffic risk without mapping | When to choose it |
|---|---|---|---|---|
| Single brand + 301 redirects | 30,000 - 55,000 EUR | 3 - 5 months | 25 - 35% | Overlapping offers, little-known acquired brand |
| Brand architecture (parent + sub-brand) | 35,000 - 75,000 EUR | 4 - 6 months | 15 - 25% | Distinct customer bases, strong local brand |
| Temporary coexistence | 4,000 - 10,000 EUR (cross-links, legal notices, shared styling) | 2 - 4 weeks | under 5% | 6 to 12 month transition before merging |
| Coexistence then single brand | 35,000 - 65,000 EUR in total | 9 - 15 months | 10 - 15% | Customers to reassure, ongoing contracts |
| Status quo (two separate sites) | 10,000 - 18,000 EUR / year of double maintenance | none | none short term | Avoid beyond 18 months |
For reference, the same project in a French regional city such as Toulouse costs 20,000 to 60,000 EUR.
What a 450-page migration costs, line by line
| Item | Range (ex. VAT) | Detail |
|---|---|---|
| SEO audit of both sites | 3,000 - 5,000 EUR | Traffic-driving pages, backlinks, keywords |
| Mapping the 450 URLs | 3,500 - 6,500 EUR | Old to new URL, page by page |
| New structure and merged content | 6,000 - 12,000 EUR | Offer pages, references, team, shared story (EN/NL) |
| Design and development | 14,000 - 25,000 EUR | Reuse of existing identity or new brand |
| 301 redirects and staging tests | 2,000 - 3,500 EUR | Automated check of every redirect |
| Post-migration monitoring (8 weeks) | 1,500 - 3,000 EUR | Search Console, 404 errors, rankings |
| Single brand total | 30,000 - 55,000 EUR |
The brand: what Google and customers need to understand
A site merger is also a commercial message. Customers of the acquired company fear a new contact person or new prices. Plan a dedicated page about the merger, a banner on the old site during coexistence and a customer email. On the Google side, use the Search Console change of address tool if the acquired domain disappears, and keep the domain for at least 12 months to maintain redirects.
The 4-phase timeline
- Month 1: audit and brand decision. Inventory of the 450 pages, scenario choice, board sign-off.
- Months 2 and 3: mapping and content. Merge offer pages, rewrite reference pages, build the redirect table.
- Months 3 to 5: design and development. Mock-ups, build, acceptance testing, 301 tests.
- Month 5 onwards: switch-over and monitoring. Go live on a Tuesday morning, daily monitoring for 8 weeks, fix 404s within 48 h.
Mini case study
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Pieter, CEO of an industrial maintenance SME in Amsterdam, acquires a competitor in Utrecht. The two sites total 450 pages and 6,500 organic visits a month, 2,400 of them on the acquired site. He chooses a single brand for 45,000 EUR, including 5,500 EUR of URL mapping. Without mapping, a 30% loss on 6,500 visits means 1,950 fewer monthly visits; at 1.2% conversion and a 6,000 EUR average contract, that is about 23 lost enquiries, or up to 140,000 EUR of potential revenue per month at risk. The 5,500 EUR mapping pays for itself with the first contract saved.
FAQ
How much does merging two websites after an acquisition cost?
Budget 30,000 to 55,000 EUR for a single brand and 35,000 to 75,000 EUR for a brand architecture in Amsterdam, based on 450 pages.
How much traffic can we lose?
Without URL mapping, losses reach 15 to 35% of organic traffic. With page-by-page 301 redirects, they usually stay under 5% after 8 weeks.
Should we keep the acquired domain?
Yes, for at least 12 months and ideally 24, to keep redirects and backlinks alive. Renewal costs 10 to 50 EUR a year.
How long should coexistence last?
Usually 6 to 12 months, long enough to reassure customers and stabilise the offer. Beyond 18 months, double maintenance (10,000 to 18,000 EUR a year) becomes waste.
When should the project start after closing?
Ideally within 30 days, with the SEO audit. The technical switch-over usually happens between month 4 and month 6.
Let's scope your project. Send us both URLs, the page count and your brand decision if it is made, and we will price the right scenario, from 30,000 to 75,000 EUR, with a 4-phase 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.
