The verdict in three sentences
A manufacturer site redesign without an SEO plan can lose 30 to 60 % of organic traffic within weeks, often permanently. A secured SEO migration plan costs between 4,000 and 11,000 EUR HT in 2026 and rests on an exhaustive 301 redirect plan, preservation of high-traffic URLs, rank monitoring and structured data. Full recovery usually happens in 4 to 8 weeks after go-live, with the loss contained under 5 %.
The migration plan line by line
The risk is not the redesign itself, but the break in the signals Google has accumulated. Here is the breakdown of a typical migration plan for a manufacturer site of 200 to 1,500 URLs.
| Line item | Standard site (4,000-6,000 EUR) | Large site (6,500-8,500 EUR) | Complex site (9,000-11,000 EUR) |
|---|---|---|---|
| Crawl + mapping of existing URLs | 700-900 EUR | 900-1,200 EUR | 1,200-1,600 EUR |
| 301 redirect plan (mapping) | 900-1,300 EUR | 1,300-1,900 EUR | 1,900-2,600 EUR |
| URL preservation + site tree | 600-900 EUR | 900-1,300 EUR | 1,300-1,800 EUR |
| Structured data (Product, FAQ, Org) | 700-1,000 EUR | 1,000-1,400 EUR | 1,400-1,900 EUR |
| Rank monitoring + logs (1 month) | 700-1,100 EUR | 1,100-1,500 EUR | 1,500-2,100 EUR |
| Post-launch technical QA | 400-800 EUR | 800-1,200 EUR | 1,000-1,200 EUR |
The 301 redirect mapping is the most critical item: every old indexed URL must point to its equivalent, with no redirect chains or 404 errors.
Recovery times and indicators to track
After go-live, a turbulent phase is normal. The table gives a 2026 order of magnitude for a well-prepared migration.
| Indicator | Week 1-2 | Week 3-4 | Week 5-8 |
|---|---|---|---|
| Organic traffic vs before | -15 to -25 % | -8 to -15 % | -0 to -5 % |
| Correctly redirected URLs | 95-98 % | 98-99 % | 99-100 % |
| Residual 404 errors | 30-80 | 5-20 | 0-5 |
| Key positions recovered | 40-60 % | 70-85 % | 90-100 % |
| Pages reindexed by Google | 50-70 % | 80-90 % | 95-100 % |
Daily monitoring in the first two weeks catches 404s and position losses before they settle in.
Need a professional website?
Kolonell builds websites that attract clients, optimized for the Sénégalese market. Free quote in 2 minutes.
Mini case study
The digital director of a manufacturer in Amsterdam is preparing the redesign of an 850-URL site generating 22,000 organic sessions/month. Without a plan, a 40 % loss would cost about 8,800 sessions/month. He chooses a migration plan at 7,500 EUR HT including 301 mapping, one month of monitoring and structured data. Result: the peak loss (week 2) is 18 %, then traffic returns to -3 % by week 7. By avoiding a lasting 40 % loss, the company preserves about 8,500 sessions/month; at a 1.8 % conversion rate and a 650 EUR lead value, that is roughly 99,000 EUR of annual pipeline saved for a 7,500 EUR cost.
FAQ
Why does a redesign hurt SEO? Because it often changes URLs, structure and code without transferring the accumulated signals. Without clean 301 redirects, Google treats the new site as unknown.
Should we keep the old URLs? Ideally yes for high-traffic pages. If the structure must change, each old URL should 301-redirect to its closest equivalent, with no intermediate chain.
How long to recover traffic? 4 to 8 weeks for a well-prepared migration. A rushed migration may never fully recover and leave a 20 to 40 % loss.
Is structured data essential? It is not mandatory but strongly recommended (Product, FAQ, Organization). It improves display in results and helps Google understand the new site faster.
When should we launch the migration? Avoid peak commercial periods. Plan intensive monitoring for the first two weeks and keep rapid-fix capacity within 48 h of go-live.
Let's scope your project. Tell us the number of URLs, the target CMS and your go-live date; we frame a migration plan between 4,000 and 11,000 EUR HT to secure your traffic. 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.
