The verdict in three sentences
A site rebuild is the moment you lose or win your SEO, rarely neutral. A structured migration engagement (audit, 301 redirect mapping, content parity, QA) costs $3,500 to $11,000 depending on site size. Done well, it returns organic traffic to its prior level within 6 to 10 weeks, with a frequent rebound above it thanks to the new version's technical gains.
The migration checklist that protects traffic
The number-one risk of a rebuild is broken signals: URLs that change without redirects, trimmed content, lost tags. The discipline is to map everything before the switch.
| Step | Goal | Deliverable | Criticality |
|---|---|---|---|
| Existing-site audit | Map traffic and pages | Prioritized inventory | High |
| 301 mapping | Old URL to new | Redirect table | Critical |
| Content parity | Keep content that ranks | Page-by-page check | High |
| Tags & structured data | Preserve title, meta, schema | Technical QA | High |
| Pre-prod QA | Catch errors before launch | QA report | Critical |
| Post-launch tracking | Detect losses fast | 30-60 day monitoring | High |
The 301 mapping is the heart of it: every indexed old URL must point to its closest equivalent, with no redirect chains or 404 errors.
Timeline and budget by site size
| Site size | SEO migration budget | Project duration | Return to normal |
|---|---|---|---|
| Brochure (< 50 pages) | $3,500-5,000 | 2-3 weeks | 4-6 weeks |
| B2B site (50-300 pages) | $5,000-8,000 | 3-5 weeks | 6-8 weeks |
| Large site (300-2,000 pages) | $8,000-11,000 | 5-8 weeks | 8-10 weeks |
| E-commerce (> 2,000 URLs) | $11,000 and up | 6-10 weeks | 8-12 weeks |
This SEO budget is separate from the cost of the rebuild itself: it is insurance against destroying an asset built over years.
Risk by type of change
| Type of change | Risk level | Key precaution |
|---|---|---|
| Visual redesign only | Low | Preserve URLs and content |
| New site structure | Medium | Exhaustive 301 mapping |
| CMS change | High | Thorough technical QA |
| Domain change | Very high | 301 + Search Console + patience |
| HTTP to HTTPS | Medium | Global 301s, update internals |
| Merging multiple sites | Very high | Gradual consolidation |
A domain change combined with a CMS change is the riskiest scenario: it requires a battle plan and close monitoring for 60 to 90 days.
Mini case study
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Nadia, digital lead at a B2B SME, prepares to move her 220-page site to a new CMS. The site generates 60,000 organic visits/month valued at $40/lead with a 2% conversion rate, i.e. 1,200 leads and $48,000 of monthly value. A rebuild with no SEO plan could risk -40% traffic for 3 months, an estimated cumulative loss of $57,600. She invests $6,500 in a migration engagement: traffic returns to normal in 7 weeks and exceeds the initial level by +12% at month 4. The benefit-to-cost ratio is decisive.
FAQ
How long should I keep 301 redirects?
At least 12 months, ideally permanently as long as old URLs still receive visits or links. Removing them too early recreates 404s and position losses.
Should I redirect everything, even old pages?
Redirect any URL that gets traffic, inbound links, or is indexed. Valueless pages can point to a relevant category rather than the homepage.
When do I measure if the migration succeeded?
Watch the first 30 days very closely (indexation, 404s, positions), then validate at 60 days. A return to the prior level in 8-10 weeks signals a controlled migration.
Can I migrate with zero loss at all?
A slight transient fluctuation is normal while Google recrawls and reindexes. The realistic goal is not zero movement, but a fast recovery and a net gain thanks to the new version.
Who should lead, the rebuild agency or an SEO expert?
Ideally both coordinate, but the 301 mapping and SEO QA must be validated by an SEO expert independent of the design work, before any go-live.
Let's scope your project. Number of pages, current and target CMS, domain change or not: describe your rebuild and an indicative budget ($3,500-11,000) and we'll frame a no-loss migration plan. 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.
