To answer shortly: Yes, redirects are bad for SEO in certain situations. Don’t get us wrong, redirects are necessary sometimes and can help your rankings. It’s the only way to transfer users (or traffic) from deleted pages to new and updated pages.
But if you want to learn how do redirects affect SEO, please read further.
How to find problems related to redirects?
For discovering all the problems created by redirects, you must use an SEO spider (like Screaming Frog, Deepcrawl, Ahrefs etc) which will crawl all the pages of your website.
After the crawling is done, you can discover an entire list of errors due to redirects. We’ll describe the most common ones which you can meet in technical SEO reports or audits.
Yes, you may wonder: “Are 301 redirects bad for SEO as well? We thought this type of redirect is ok”. Well, the problem is not that a 301 redirect was created, but that the page which was redirected still receives links (internally, from previous redirects or from other websites).
So instead of reaching directly to the destination page when clicking on a link, both users and search engines crawlers will have to go through a redirect first. This will make the pages loading speed slower (which is bad for user experience), will consume more bandwidth, and will waste link equity and crawl budget.
HTTP to HTTPS redirect
You may ask yourself again: “Why is bad to redirect an unsecured page to a secured one?” The problem is not that unsecured pages have been redirected to secured pages. This is, actually, a very good thing because HTTPS is one of the ranking signals for Google. But for this particular reason, crawlers show this error: Google will see too HTTP pages because they are still receiving links (internally or externally).
HTTPS to HTTP redirect
As we mentioned above, HTTPS is one of the ranking signals for Google. Therefore we strongly advise against redirecting HTTPS (secure) URLs to HTTP (not secure) ones.
Canonical points to redirect
These are website pages that have a canonical link pointing to a redirecting URL.
Sometimes you can have similar content or products under multiple URLs. This leads to duplicate content which can harm your website (its rankings).
Therefore, similar or duplicate pages must have a “canonical” tag in which you specify which is the most authoritative version you want search engines to show in search results.
But a redirecting URL specified as canonical can be misinterpreted by the search engines. As a result, a wrong (non-canonical) page version can be indexed.
A redirect chain is a series of at least 2 redirects between the initial URL and the destination URL (so from page A->B->C and so on).
An even bigger problem is when the redirect chains are created from 302 redirects (which, again, are meant only for pages moved temporarily), or when a redirect chain is a mix between secured (HTTPS) and unsecured (HTTP) pages.
A redirect loop can happen in 2 situations.
One is when a URL redirects to itself (page A->page A->…)
The other one is when a redirect chain redirects to one of the URLs within the chain (example page A->B->C->A->…).
Page has links to redirect
These are the pages that have links to redirecting URLs.
A single page can have dozens or even hundreds of links to redirects. This consumes much more bandwidth and crawl budget than necessary (so search engines will take longer to discover and index more of the unique and fresh content). Also, this could lower your rankings because it wastes link equity (10%-15% for every redirect) and influences User Experience (visitors may “bounce” because pages loading time are higher).
External 3XX redirect
It means that you link to other websites, but these links step through different types of redirects (301, 302 etc). You should be very careful because these might lead to totally different pages (or websites) than the original ones. This can be confusing for both users and search engines crawlers. Thus you should review all external redirects to make sure you don’t link to irrelevant or spammy content.
These are the pages where SEO spiders have discovered redirected resources.
3XX page receives organic traffic
Redirected pages still appear in SERP. This can occur when you redirect a page, but search engines didn’t crawl it yet. In search results, users must find the current live pages, not the old ones which have been redirected.
3XX redirect in the sitemap
The sitemap contains pages that have been redirected. It’s a problem because the sitemap gives search engines a hint about which are the most important pages you want to be crawled and indexed. Thus including pages which no longer exist gives mixed signals to search engines and, as a result, they may choose to ignore the sitemap.
As you can see, redirects do affect SEO and fixing problems they create is an ongoing process. Pages are deleted all the time and are replaced with new ones. But redirects will not hurt your SEO anymore if you take care of all aspects described in this article.