This is always a question in SEO that comes up again and again, but I believe that the answer is still the same. Subdomains vs Subfolders – which is best for SEO?

This question often arises when a website owner would like to create a blog for their website. He will have 3 options.

1. Place the blog in a subfolder:

2. Place the blog on a subdomain:

3. Place the blog on a completely new domain:

There could be many reasons for using a subdomain or a completely new domain in this instance. It could be technically easier to set up; you might want to target seperate branding; you might want to target a different location or language.

But, for SEO purposes, I would still always advise my clients to use a subfolder.


Some clients I have come across have used a subdomain thinking that this would be good for their SEO. This is under the theory that the original domain, and the subdomain will both have an opportunity to rank in a similar topic, and therefore they can dominate the search engines. But the opposite is true.

All this technique is doing is spreading the inbound links across two sites, therefore hurting the ability for both of them to rank.

Scenario 1

Consider this scenario. You have opted to use a subdomain for your blog. You already have 50 good backlinks heading to your main domain, and you have managed to obtain another 50 good backlinks to your subdomain.

50 Links

50 Links

And lets say, with these backlinks, and with all other ranking factors, that your main domain and subdomain have the domain authority to get you ranking both on the 2nd page of Google for “keyword 1”. Great! Page 2 will get you some traffic.

Scenario 2

But now consider the scenario where you have opted to use a subfolder for your blog. You already have 50 good backlinks heading to your main domain, and you have managed to obtain another 50 good backlinks to your subfolder blog. This means that you now have 100 backlinks to your main domain!

100 Links

Having double the links going to your main domain will dramatically increase it’s domain authority. This means that any page on the site – including the blog in the subfolder – will be far more likely to rank for any keyword!

So, if you were ranking on page 2 (twice) for “keyword 1” in Scenario 1, you will likely be ranking on page 1 (once) in Scenario 2. I know which I would prefer.



Googlers, over the past few years, have made a few statements to give us confidence that Google can now effectively identify content on a subdomain, and associate it with your main domain. The message being that we don’t have to worry about placing content on several domains. You can view John Mueller from Google here stating:
“If you want to put a blog on your main website in a subdirectory that’s fine, if you want to use a subdomain that’s fine. If you want to use a different domain name, that’s possible too. So all of these ways are essentially possible and I wouldn’t say that any one or the other is superior in any magical way.”

Although Google may have made huge improvements over the years with this, there are still case studies coming up from several websites where there are still huge risks from using subdomains. Craig Emerson of Blogging Flail uses a good case study in which he moves a blog from a subdomain to his main site, and saw dramatic ranking improvements within 2 weeks. Another case study from I Want My Name saw the website take a hit in search traffic when they placed their blog on a subdomain. This didn’t recover after 6 months before they reverted their blog back to a subfolder.


Although there is some conflicting information regarding this, any evidence out there against subdomains would lead us to the conclusion that using a subdomain for SEO purposes poses some risks. And risk is not something that we like in SEO. We know that subfolders work, so why use a potentially unsafe option.

Safe and risk-free SEO is what our SEO Consulting Team at Supreme Optimization always promotes. This is the strategy we take to long-term sustainable rankings.

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