The verdict in three sentences
If your code is under four years old, your Core Web Vitals are green and only the design feels dated, a partial redesign at EUR 5,000-10,000 is enough. If the CMS is unmaintained, technical debt blocks every change and mobile conversion caps at 40 %, you must rebuild (EUR 18,000-35,000). In every case, the costliest variable is not design: it is the existing SEO you risk destroying.
Partial redesign or rebuild: the decision matrix
The question is not aesthetic, it is technical and commercial. A site converting at 3 % with a dated design earns more than a stunning one at 0.8 %. Cross-check seven criteria before you sign.
| Criterion | Partial redesign (EUR 5-10k) | Rebuild (EUR 18-35k) |
|---|---|---|
| Code age | < 4 years | > 5 years |
| CMS maintained | Yes, up to date | No or end of life |
| Core Web Vitals | LCP < 2.5 s | LCP > 3.5 s |
| Technical debt | Low/moderate | Blocking |
| Conversion rate | > 2 % | < 1 % |
| Mobile responsive | Fine | Missing/broken |
| Desired timeline | 4-6 weeks | 10-14 weeks |
Simple rule: three or more lines in the right column and a rebuild is justified. Otherwise you are paying for new build to fix a problem EUR 8,000 of redesign would solve.
Cost, risk and traffic impact
The real danger of a redesign is losing organic traffic when URLs, structure or content change without a migration plan. Here are the 2026 orders of magnitude observed.
| Scenario | Investment | Traffic loss if mishandled | Timeline | Expected payback |
|---|---|---|---|---|
| Visual redesign only | EUR 5,000-8,000 | 0-5 % | 4 weeks | 3-5 months |
| Partial redesign + SEO | EUR 8,000-14,000 | 5-8 % | 6-8 weeks | 4-7 months |
| Full rebuild | EUR 18,000-35,000 | 8-25 % | 10-14 weeks | 6-10 months |
| Rebuild + failed migration | EUR 18,000-35,000 | 25-40 % | 14+ weeks | 12-18 months |
A well-run rebuild budgets EUR 2,000 to 3,000 for 301 redirects, URL mapping and preserving content that performs. It is the line item cut first and regretted most.
Mini case study
Thomas, marketing director of a 45-employee industrial SME in Lyon, is torn. His site is six years old, runs on an unmaintained WordPress, converts at 0.9 % and loads in 4.1 s on mobile. Five criteria point to a rebuild. He invests EUR 24,000, including EUR 3,000 for a redirect plan. Result over eight months: LCP at 1.3 s, conversion at 2.4 %, meaning +167 % leads. With an average project value of EUR 8,000 and 6 extra qualified leads per month converting at 20 %, the site generates EUR 9,600 in additional monthly revenue. Payback in 2.5 months once traffic stabilises.
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FAQ
Does a redesign always cost SEO?
No, if you preserve performing URLs or implement exhaustive 301 redirects. A careful migration caps the loss at 0-8 % over 4 to 8 weeks, then traffic recovers. Without a plan, the drop hits 25-40 %.
How long should a B2B rebuild take?
Allow 10 to 14 weeks for a 15-to-40-page site, scoping and QA included. Unready content is the top cause of delay: it often adds 3 weeks.
Can I keep my current hosting?
Often yes for a redesign, rarely for a modern rebuild (headless, Next.js). Performant hosting costs EUR 60 to 200/month and directly improves your Core Web Vitals.
How do I know if my technical debt is blocking?
If every small change takes days of dev, if you can no longer update the CMS without breaking the site, or if nobody will touch the code: the debt is blocking.
Is a redesign a bad choice?
Not at all. On healthy code under 4 years old, a EUR 6,000 redesign restores visual credibility and conversion without the risk or cost of a rebuild.
Let's scope your project. Send us your current URL, your indicative budget (redesign EUR 5-10k or rebuild EUR 18-35k) and your deadline: within 48 h we tell you which option maximises your ROI. 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.
