How to check if a domain is available
It sounds like a yes-or-no question. It mostly is. But the obvious way of checking, visiting the site and seeing nothing, gives the wrong answer constantly. Here's how it actually works.
Reviewed May 2026
The instinct, when you want to know if a domain is free, is to type it into a browser. If a site loads, it's taken; if nothing loads, it's open. That second half is wrong, and it's wrong often enough to waste real time. A domain can be registered for years and never show you a single page.
Registered and 'has a website' are different things
Plenty of registered domains have no site. They're parked, held by someone sitting on the name, bought defensively by a company that didn't want a competitor to have it, or attached to an email address and nothing else. Visit one and you'll get an error, a blank page, or a generic parking screen. None of that means you can register it. The owner just hasn't pointed it anywhere. So 'the website doesn't load' tells you almost nothing.
The fast check is DNS
The quick, reliable signal is DNS. Every registered domain gets name servers delegated to it at the registry; that's the step that makes a domain a working domain. You can ask the DNS system one simple question: does this name have name servers? If the answer is NXDOMAIN, the registry has no record of the name, and in nearly every case that means it's unregistered. If name servers come back, it's taken. This is what the checker on this site does first, straight from your browser, which is why it's instant.
What NXDOMAIN means
NXDOMAIN is the DNS system saying 'I have no entry for that name.' It's the cleanest available-signal you can get without contacting a registrar. It isn't flawless. A domain can be registered and still have no name servers for a while, freshly bought or parked without DNS, which is why a careful check confirms a second way.
DNS versus WHOIS
There are two systems people mean when they talk about checking a domain. DNS is the live routing layer; it tells you whether a name resolves. WHOIS is the registration record; it tells you who registered a domain and when, and when it expires. WHOIS is the authoritative answer to 'is this registered,' but it's slower, rate-limited, and increasingly redacted for privacy. DNS is fast and public. A solid check leans on DNS for speed, then confirms against the registry when the DNS answer is ambiguous.
The catch: available isn't buyable
Even a clean NXDOMAIN doesn't promise you can register the name at the standard price. Some names are reserved by the registry. Some carry premium pricing, where the registry has flagged a name as valuable and charges a multiple for it. Some are tangled up with a trademark, which a registrar may not stop you buying but a lawyer later will. A DNS check sees none of this. It tells you the name is unclaimed; it can't tell you what claiming it costs or risks.
So, how to actually check one
Use a checker that does both steps (a DNS lookup for speed, then a registry check to confirm) rather than eyeballing whether a site loads. If you don't have a specific name yet, describe what you're building and let the generator propose some, each one checked the same way. Either route gives you a real answer in a second or two.