The verdict in three sentences
A successful rebuild is not judged by its design but by the organic traffic curve 60 days after go-live. The critical item is the 301 redirect plan, not the CMS: a single broken redirect chain can wipe out months of rankings. Budget 2,500 to 6,000 EUR for a managed SEO migration, targeting a maximum 10 % drop and a return to baseline within 8 to 12 weeks.
How much an SEO migration costs by URL volume
Migration pricing does not depend on the number of visible pages but on the total number of indexed URLs (pagination, filters, old articles, PDFs). The higher the volume, the more time-consuming the redirect mapping.
| Indexed URL tier | SEO migration package | 301 redirect plan | Timeline |
|---|---|---|---|
| < 100 URLs | 2,500 EUR | Included | 1 week |
| 100 to 500 URLs | 3,500 EUR | Included | 2 weeks |
| 500 to 2,000 URLs | 4,800 EUR | +0.80 EUR/URL above 500 | 3 weeks |
| 2,000 to 5,000 URLs | 6,000 EUR | +1.20 EUR/URL above 500 | 4 weeks |
| > 5,000 URLs | Custom quote | +1.50 EUR/URL above 500 | 5-6 weeks |
The package includes exporting the existing crawl, mapping old URL to new URL, auditing server logs to identify pages actually crawled by Google, and 60 days of post-launch monitoring.
The D-30 / D+90 plan that protects traffic
A migration is prepared one month before the switch and monitored three months after. The content freeze of 2 to 3 weeks before go-live is non-negotiable: editing text during migration mixes two variables and makes any diagnosis impossible.
| Phase | Period | Key actions |
|---|---|---|
| Mapping | D-30 to D-20 | Full crawl, Search Console export, inventory of high-traffic URLs |
| Redirect table | D-20 to D-10 | 301 correspondence table, validation of priority URLs |
| Content freeze | D-15 to D0 | No editorial changes, tag preparation |
| Switch | D0 | Deployment, 301 activation, sitemap submission |
| Monitoring | D+1 to D+90 | Weekly tracking of 404s, top 10 positions, organic sessions |
The KPIs to watch after the switch
Three indicators are enough to know whether the migration is going well. A drift on any one triggers an immediate corrective action.
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| KPI | Alert threshold | Check frequency |
|---|---|---|
| Organic sessions | Drop > 10 % over 7 days | Daily week 1, then weekly |
| Keywords in top 10 | Loss > 15 % of portfolio | Weekly |
| 404 errors | > 2 % of crawled URLs | Daily weeks 1-2 |
| Indexed pages | Fall > 20 % in Search Console | Weekly |
| Average crawl time | Rise > 30 % | Twice weekly |
Mini case study
Thomas, marketing director of a B2B industrial distribution SME in Dublin, approves a rebuild of his site with 1,400 indexed URLs. The migration package comes to 4,800 EUR (500-2,000 tier) plus 720 EUR of redirects above 500 URLs (900 URLs x 0.80 EUR), i.e. 5,520 EUR. His site generates 42,000 organic sessions per month worth about 18 leads. Without a migration plan, a typical 35 % drop over three months would cost him 6.3 leads/month for 12 weeks, nearly 19 lost leads. At an average lead value of 1,200 EUR, the investment pays for itself by avoiding a single traffic loss.
FAQ
Does a rebuild always reduce traffic? No, if the redirect plan is complete. A temporary drop of 5 to 10 % is normal while Google recrawls; beyond 15 %, there is a technical fault to fix.
How long to recover my traffic level? On average 8 to 12 weeks for a B2B site under 2,000 URLs, provided the content structure and redirects are clean.
Should I keep the same URLs? Ideally yes. Every URL change needs a 301; keeping high-performing URLs reduces both risk and mapping cost.
Should the blog migrate at the same time? Yes, because it often concentrates 40 to 60 % of a B2B site's organic traffic. Excluding it creates two migrations and doubles the risk.
Are JavaScript redirects any good? Not for SEO. Only server-side 301 redirects reliably pass link equity and are recommended by Google.
Let's scope your project. Tell us your indexed URL volume, your current CMS and your target switch date: we'll price the migration package and the matching redirect 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.
