Planning a URL migration without losing rankings

Why migrations lose rankings

When URLs change, every ranking signal tied to a URL (links, history, index entries) has to be transferred to a new address. The transfer mechanism is the 301 response, and the transfer is only clean when every single old URL has one new home. The failure pattern is the same everywhere: content moved, links from the old pages point nowhere, and search engines spend months reconciling what they thought was one page. The 301 redirect reference is the contract every redirect in this plan must satisfy.

Step 1: take stock of the old site

Export the full URL list from the crawler or the sitemap. Include:

• Every page with meaningful traffic or links (the ones that matter).
• Pages deep in navigation (they still matter but get a batch redirect).
• The odd items: images, PDFs, pages with query parameters, and any URL that users have bookmarked or linked externally.

For a small site this list is a spreadsheet; for a large one it is a crawl export. It is the old inventory that the map will cover.

Step 2: build the old-to-new map

Every old URL gets exactly one target, chosen by rules before exceptions:

1. The one-to-one rule: a page that survived with the same content redirects to its new equivalent (the highest-value redirect type).
2. The consolidation rule: multiple old thin pages that merge into one new page all redirect to that page.
3. The section rule: if an old section disappears, map its members up to the nearest still-alive parent page, not to the home page.
4. The fallback rule: anything without a natural target maps to the site root or a category hub, never to a dead link.

Step 3: 301, not the others

Every row is a 301 Permanent Redirect (for permanent moves), implemented as a redirect map or in the server config. The redirect map article has the mechanical recipe. There is no excuse for a 302 or a soft-404 on a permanent move; search engines and browsers treat a 301 as a permanent assignment of the URL.

Step 4: test before the switch

1. Confirm every old URL answers with 301 to exactly its mapped target (the crawler follows).
2. Run the live URL test in Search Console for a sample.
3. Keep the old URLs working until the mapping is verified; turn on the redirects only when you flip the site, not before.

Step 5: measure after

The swap creates a transition where old URLs 301 to new ones. The confident signal is the Search Console flow:

1. The Pages report will show old URLs with a Page with Redirect reason for a while; that is the transfer in progress, not a fault.
2. After a few weeks the new URLs appear indexed with the old equity.
3. Compare the performance before vs after on a like-for-like window, not day to day.

The domain change version of this plan is for changing hostname, which has different traps, and the 301 guide is the piece that every mapping step above references.