A redirect sends a visitor — and a crawler — from one URL to another, and on the surface, 301 and 302 look like they do the exact same thing: the browser lands somewhere else, the visitor barely notices. Underneath, they carry completely different meaning to a search engine, and using the wrong one is one of those mistakes that causes no visible symptom while quietly affecting rankings for months.

The actual difference

301 means "moved permanently." It tells search engines the old URL is gone for good and the new one should be treated as its replacement — ranking signal, link equity and indexing history transfer to the new URL, and over time Google drops the old URL from its index entirely in favor of the new one.

302 means "moved temporarily." It tells search engines the old URL is still the real, permanent one — this new location is just a temporary stop. Google generally keeps the original URL indexed and doesn't transfer ranking signal to the destination, because you've explicitly said this isn't permanent.

The HTTP status code is the only technical difference a server sends, but the SEO consequence of picking the wrong one is substantial: use a 302 for something that's actually permanent, and you can leave ranking signal stranded on a URL you've effectively abandoned, sometimes for months, before Google decides to treat it as permanent anyway through its own heuristics.

When to use each

Use a 301 for:

  • ◆A permanent URL structure change (migrating from /blog/post-name to /articles/post-name)
  • ◆Domain migrations (moving from oldsite.com to newsite.com)
  • ◆Consolidating duplicate or near-duplicate pages into one canonical version
  • ◆Retiring an old page permanently in favor of a genuinely equivalent new one
  • ◆HTTP to HTTPS redirects (a 301 is standard practice here, even though it's not strictly a content move)

Use a 302 (or 307) for:

  • ◆A/B testing, where traffic is being split and the original URL needs to stay the "real" one in search results
  • ◆Geotargeting or device-based redirects that change based on context, not a permanent content move
  • ◆A page temporarily down for maintenance, where you don't want the destination replacing it in the index
  • ◆Seasonal or promotional redirects that will be reversed later

A genuinely useful test: if you'd be upset to see the original URL still ranking in six months, you wanted a 301. If you'd be upset to see the destination replace the original permanently, you wanted a 302.

The mistake that costs the most: platform migrations

The highest-stakes version of this mistake happens during a full platform migration — WooCommerce to Shopify, WordPress to a custom build, or any move that changes the entire URL structure at once. Every old URL needs an explicit, one-to-one mapped 301 to its genuine new equivalent. A blanket redirect sending every old URL to the new homepage is common, fast to implement, and genuinely damaging — it throws away the specific ranking signal each individual page had built up, replacing years of accumulated authority with a single generic redirect that search engines treat far less favorably than a real one-to-one mapping.

Tip Before any migration, export your current top-performing URLs (by traffic or backlinks, from Search Console or your analytics) and build the redirect map from that list first. Getting the highest-value 20% of your URLs mapped correctly matters more than achieving 100% coverage of every low-traffic page on day one.

Checking your redirects

Redirect chains — where one redirect leads to another, which leads to another — are a related, equally common problem: each additional hop adds latency, and a chain long enough (generally more than 2-3 hops) can cause crawlers to give up following it entirely. Our free redirect checker follows a URL's full chain, showing every hop's status code and timing, so you can see exactly how many redirects deep a URL goes and whether it ends where you intended.

Redirects are one piece of a bigger technical migration picture — see our guide to migrating e-commerce platforms without losing SEO rankings for the full checklist, and our web development services if you're planning a migration and want the redirect mapping done properly from the start.