The verdict in three sentences
In 2026 in Berlin, a big-bang B2B website rebuild costs EUR 15,000 to 40,000 delivered in 3-4 months, while a phased rebuild is paid EUR 4,000 to 9,000 per batch over 6-9 months. Phased smooths cash flow, reduces SEO risk by migrating page by page and lets you measure before generalising. Big-bang stays relevant when the rebuild is structural or when a tight marketing deadline demands it.
Big-bang: rebuild all at once
The big-bang replaces the entire site in a single delivery. It is the choice when the old site is technically doomed or when a deadline (trade show, rebrand) sets a firm date.
| Item | Range EUR | Share of budget |
|---|---|---|
| Scoping + UX | 3,000 - 7,000 | 18% |
| UI design | 3,000 - 8,000 | 20% |
| Development | 6,000 - 18,000 | 45% |
| Content migration + SEO | 2,000 - 5,000 | 12% |
| QA + go-live | 1,000 - 2,000 | 5% |
| Total | 15,000 - 40,000 | 100% |
Upside: full consistency from day one. Risk: a single cutover day concentrates all the SEO and technical risk.
Phased: rebuild in batches
The phased rebuild splits the site into batches (home, offers, blog, client area) delivered one after another, coexisting with the old site via routing. The comparison below clarifies the trade-off.
| Criterion | Big-bang | Phased |
|---|---|---|
| Total cost | EUR 15,000 - 40,000 | EUR 18,000 - 45,000 |
| Payment | 3-4 close instalments | Batches of EUR 4,000 - 9,000 |
| Overall timeline | 3 - 4 months | 6 - 9 months |
| SEO risk | Concentrated (cutover) | Diluted (page by page) |
| Time-to-market 1st batch | 3 months | 4 - 6 weeks |
| Internal load | Intense then none | Spread out |
The cumulative total of the phased approach is often 10-15% higher, but that premium buys a real reduction in risk and smoothed cash flow.
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Mini case study
Julie, marketing director of a B2B software vendor in Berlin, has an annual budget of EUR 30,000. A big-bang would consume it all at once with 3-4 months without a visible deliverable. She opts for a phased rebuild: batch 1 (home + offers) at EUR 8,500 delivered in 5 weeks, then 3 batches of EUR 7,000 spread over the year. From batch 1, her demo-request conversions rise 14%, which funds the following batches both psychologically and budget-wise. No SEO dip is observed.
FAQ
Which approach costs less in total? Big-bang, slightly: EUR 15,000-40,000 versus EUR 18,000-45,000 cumulatively for phased. But phased buys risk reduction and faster time-to-market.
Which protects my SEO best? Phased, because it migrates page by page with controlled redirects, avoiding the sharp drop possible during a poorly prepared big-bang cutover.
How long until the first visible result? In phased, the first batch ships in 4 to 6 weeks. In big-bang, you wait for full delivery, i.e. 3 to 4 months.
Is big-bang ever mandatory? Yes, when the rebuild changes the underlying technology (CMS, architecture) and batch-by-batch coexistence would be technically more expensive than a direct replacement.
How do I smooth cash flow? Phased bills in batches of EUR 4,000 to 9,000, which avoids committing EUR 30,000 at once and aligns spend with measured results.
Let's scope your project. Tell us your annual budget, your deadline and the state of your current site: we will recommend big-bang or phased, with the numbers. 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.
