When deciding to move web pages on a site or blog posts on a blog, knowing the difference between a 301 redirect and a 302 redirect is critical, as each conveys different information to search engines like Google. Simply put, the search engine needs to know whether to continue ranking the old page or to replace it entirely in the rankings with the new one. By using the proper redirect this is made perfectly clear and you can avoid any confusion and the corresponding drop in the search rankings while migrating pages to new locations. Let’s explain in which situations a 301 redirect is appropriate (most often) and when is a 302 redirect is better (rarely)?
301 vs. 302
Each redirect has a distinct function and usage for relocated pages; the 301 redirect is used when redirecting a web page permanently, while the 302 redirect is solely used for temporary redirections. Although visitors will not see any visual difference between these redirects in their browsers, search engines will automatically read the information and act accordingly.
If it’s a 301 redirect, they know to rank the new page as it will be permanently replacing the old one. A 302 redirect may indicate that there’s some temporary restructuring but the search engine spiders should not rank this new URL as it will not become the permanent URL.
Here is the technical definition. Scroll down to 10.3.2 301 Moved Permanently http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html
Using the Wrong Redirect
Unfortunately, any mixed signals could result in a decline in search rankings as a result of the search engine misunderstanding the server-side directions that these redirects provide. For instance, if a webmaster uses a 301 redirect for a temporary page, the search engine may put more emphasis on the temporary page and adversely affect rankings in the future when the temporary redirect is removed and traffic is again directed back to the original page, which has now regretably lost its search rank to the temporary page.
Similarly, a 302 redirect used on a permanently redirected page could greatly delay the ranking of the new page. In general search engines such as Google provide much more leniency in these instances; since 302 redirects are far more commonly used, search engines may scan the page further to determine whether the redirect should be permanent or temporary.
Time and time again I’ve seen websites that previously had fantastic organic traffic lose a large number of their visitors due to inadequate transitions or usage of redirects. This can represent a massive decline in sales and affect a company’s bottom line.
When is it Appropriate to use a 301 or a 302?
If you are moving your site from one root domain to another, it’s important that you do your best to keep the existing URL structure. Changing all of your URL’s sends the search engine spiders the signal that there is a massive change. In some cases, this may cause the site to lose authority or trusted status and thus result in a decline in the rankings. And definitely the appropriate redirect to use is a 301 redirect as this minimizes any loss in rankings.
Many people also use a 301 redirect to send the www version of the site to the non-www version of the site. This is a good idea which prevents the link juice from being split between two domains, and tells Google to see your domain as one and the same. You can also set this (called the canonical URL) in Google WebMaster Tools.
Finally, if you are switching your CMS or implementing a new shopping cart system, it may be inevitable that URL schema will be different. In that case, you’ll want to set up page to page 301 redirects in your htacess file, telling the search engines that page A moved to URL A, page B moved to URL B, etc. Using page to page 301 redirects will help you keep your site’s search rankings and traffic. We have seen projects with over 200,000 redirects work without an issue with the search engines.
What about 302 redirects, when should those be used? Let’s say, for example, you are running a holiday promotion. You can create a landing page, and do a 302 redirect from your category page to the promo page. Then, after the promotion ends, you can revert all traffic back to the original page. There will be no search engine “juice” passed to the temporary page, and when the redirect is removed, everything will go back to normal. This is one of the ONLY times that 302 redirects should be used.
Concluding Redirection Suggestions
Be careful with your redirects! Before you make any changes to your site, consult a professional. Using the wrong redirects can have dreadful, unnecessary consequences. It is one of the most avoidable causes for loss of traffic and rankings. Not only do you need to be sure which to use, you also need to make sure the redirects are implemented correctly. Do your research first! If you are also concerned about losing page rank even when implementing the right redirect, read this article http://blogwranglers.com/im-migrating-to-wordpress-will-301-redirects-diminish-my-pagerank/ to ease your concerns. If you are moving a site or blog, after it goes live, be sure to check your logs for 404 Error pages and then redirect them appropriately.
What experiences or concerns do you have with redirects? Share in the comments below.