Key takeaways
- A root domain is the name you register, such as example.com. It is the domain name plus the top level domain, with nothing in front.
- Subdomains like blog.example.com sit in front of the root domain. Top level domains like .com sit at the end. Paths like /pricing come after.
- SEO tools count backlinks, referring domains, and authority scores at the root domain level, so a link to any subdomain or page counts for the whole site.
- Google mostly treats a subdomain as part of the same site but can treat it as separate. A subdirectory is always part of the site. For SEO, subdirectories are the safer choice.
What is a root domain? It is the part of a web address you actually own: the name plus its ending, like zutrix.com, with nothing before it and nothing after it. Every other part of a URL hangs off that root. This guide explains each part of a domain name in plain words. It shows the difference between a root domain, a subdomain, and a top level domain. And it covers why SEO tools measure everything at the root, which is the part that matters for rankings and links.
We build Zutrix, an SEO platform, and our backlink and rank tracking tools report at the root domain level like everyone else's. That is why this guide exists: the term shows up in every report and few tools explain it. If you want to see how the numbers use it, read referring domains vs backlinks next.
What is a root domain?
A root domain is the registered name of a website: a chosen word plus a top level domain. In zutrix.com, "zutrix" is the second level domain, the part you picked, and ".com" is the top level domain, the part the registry controls. Together they form the root domain. You buy it from a registrar, you renew it yearly, and everything else on the site is built underneath it.
The root domain meaning is easiest to see by stripping a URL down. Take https://blog.example.com/seo/tips?page=2. Remove the protocol, https. Remove the subdomain, blog. Remove the path, /seo/tips, and the query, ?page=2. What is left, example.com, is the root domain. Some tools call it the apex domain, the naked domain, or the bare domain. They all mean the same thing.
| Part | Value | What it is |
|---|---|---|
| Protocol | https:// | How the browser talks to the server |
| Subdomain | blog | A section in front of the root, optional |
| Second level domain | example | The name you chose |
| Top level domain (TLD) | .com | The ending, run by a registry |
| Root domain | example.com | The name you registered |
| Path | /seo/tips | A page or folder on the site |
| Query string | ?page=2 | Extra instructions for the page |
Root domain vs subdomain
A subdomain is a label added in front of the root domain, separated by a dot. blog.example.com, shop.example.com, and app.example.com are three subdomains of one root. The owner of example.com can create as many as they like without buying anything. Each can point to a different server and run different software.
The most common subdomain is www. www.example.com and example.com are technically different addresses, which is why sites redirect one to the other. Pick one, redirect the other, and use the same one everywhere. Google treats them as the same site once the redirect is in place.
Subdomain vs subdirectory for SEO
A subdirectory is a folder on the root domain: example.com/blog instead of blog.example.com. Both hold the same content. The difference is how clearly Google sees them as one site. A subdirectory is always part of the root domain. A subdomain usually is, but not always, and its links may not pass strength to the main site as reliably.
| Use case | Better choice | Why |
|---|---|---|
| Blog or guides | Subdirectory, example.com/guides | Links and content strengthen the main site |
| Different language sites | Either, with hreflang | Both work if tagged correctly |
| Web app behind a login | Subdomain, app.example.com | Separate server, not meant to rank |
| Help docs on a third-party platform | Subdomain, docs.example.com | Easier to host elsewhere |
| Regional store | Subdirectory, example.com/uk | Shares authority |
Zutrix moved its guides from a blog subdomain to a subdirectory for exactly this reason. Everything Google learns from the guides now counts for the root domain. Our technical SEO checklist includes the redirect steps for a move like that.
What is a top level domain?
The top level domain, or TLD, is the last part of the root domain: .com, .org, .io, .co.uk. Generic TLDs like .com and .net are open to anyone. Country code TLDs like .uk and .de signal a country to Google and can help local rankings there. Newer TLDs like .app and .shop work the same as .com for ranking. Google has said it treats them equally.
Two-part endings like .co.uk are still one TLD for SEO purposes. The root domain is example.co.uk, not co.uk. Tools handle this with a public list of suffixes so they do not count every .co.uk site as one domain.
1
Root domain per registered name
Unlimited
Subdomains you can create under it
1,500+
Top level domains in use
Why the root domain matters for SEO
Almost every SEO metric is counted at the root domain. Referring domains count how many different root domains link to you, so ten links from ten pages on one site are one referring domain. Authority scores like Domain Rating and Domain Authority are calculated for the root. Rank trackers report which root domains hold each position. When a tool says "domain", it nearly always means root domain.
That has two practical effects. A link to any page or subdomain of your site counts toward the whole root domain's strength. And a competitor's subdomain shares that competitor's authority, so blog.bigbrand.com is harder to outrank than its size suggests. Our guide on how to check backlinks shows how tools report both levels.
Common mix-ups with domain name parts
- +Redirect www to non-www or the reverse, and use one version everywhere.
- +Put content you want to rank in a subdirectory of the root.
- +Check referring domains, not raw backlinks, when judging a link profile.
- xRegister a keyword-stuffed domain hoping it ranks. Exact match domains stopped helping years ago.
- xAssume a subdomain automatically inherits the main site's rankings.
- xConfuse a domain with a URL. The domain is the name. The URL is the full address of one page.
FAQ
Common questions
Written by the Zutrix team
Last reviewed September 16, 2026
Zutrix has built rank tracking and SEO software for more than eight years. Our guides come from the same team that runs the product, and every how-to is checked against what we see in real ranking data across the keywords our customers track. We write them for people who are new to SEO and for agencies who want a clear answer fast.
Search volume and difficulty figures come from live Google results and third-party keyword data.
Sources and further reading