The verdict in three sentences
Every time a rebuild changes URLs, a 301 redirect must send each old address to its new one, or Google loses the link and your traffic drops 10-40 %. A professional plan (mapping, redirect matrix, tests, 90-day Search Console monitoring) costs GBP 1,000-3,000 in 2026 and takes 1-2 weeks to prepare. It is the cheapest insurance line in a rebuild project: skip it and you erase years of SEO.
URL mapping: the starting point
You list every old URL (crawl + Search Console + Analytics) and rank them by priority based on traffic and rankings. Here is the structure of a typical redirect matrix.
| Old URL | New URL | Type | Priority |
|---|---|---|---|
| /our-services | /services | 301 | High |
| /product-a-2020 | /products/product-a | 301 | High |
| /blog/old-article | /blog/new-article | 301 | Medium |
| /removed-page | /parent-category | 301 | Medium |
| /promo-2023 | (intentional 410) | 410 | Low |
The rule: never a redirect chain (301 to 301 to 301) or a loop. Each old URL points straight to its final, relevant, live target.
Cost, timeline and risk of the service
Budget depends on URL count and sitemap complexity. Here are 2026 ballpark figures.
| URL volume | Price 2026 | Timeline | Risk if skipped |
|---|---|---|---|
| < 50 URLs | GBP 1,000-1,500 | 1 week | -10 to -20 % traffic |
| 50-200 URLs | GBP 1,500-2,200 | 1-2 weeks | -15 to -30 % traffic |
| 200-500 URLs | GBP 2,200-3,000 | 2 weeks | -25 to -40 % traffic |
| 90-day Search Console monitoring | GBP 400-800 | 3 months | Ongoing fixes |
Post-launch monitoring is essential: you watch for 404 errors, missing redirects and ranking movement in Search Console for 90 days, fixing as you go.
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Mini case study
Emma, acquisition lead at a B2B publisher in London, is preparing a rebuild that changes 180 URLs. Her site draws 62 % of its leads from SEO, about 150 leads/year. Without a redirect plan, a 30 % traffic loss would cost 45 leads/year; at a 9 % close rate and a GBP 5,000 average contract, that is GBP 20,250 in lost annual revenue. The professional redirect plan with 90-day monitoring costs GBP 2,700. The return is immediate: it protects over GBP 20,000 of revenue for GBP 2,700.
FAQ
What happens if I miss redirects during a rebuild? The old URLs return 404 errors, Google de-indexes the pages, and organic traffic drops 10-40 % for 2-4 months, sometimes longer if the plan is never fixed.
How long should I keep 301 redirects? At least 12 months, ideally permanently as long as old external links point to the original URLs. A 301 passes on most of the old page's SEO value.
What is the difference between a 301 and a 302? A 301 is permanent and passes SEO "juice"; a 302 is temporary and does not pass it reliably. For a rebuild, you always use 301s.
Should I redirect pages with no traffic? High-traffic, well-ranked pages come first, but you also redirect URLs with external backlinks, even without direct traffic, so as not to lose their authority.
How long to recover rankings after a successful rebuild? With a good redirect plan, rankings usually stabilize in 2-8 weeks. Without a plan, recovery takes months and stays incomplete.
Let's scope your project. Send us the URL count of your current site and the planned rebuild date (budget GBP 1,000-3,000 by volume): we deliver the mapping, the 301 matrix and 90-day Search Console monitoring. 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.
