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A few weeks ago DomainTools saw its one billionth unique domain name. That’s a lot of domains! For context, there are about 350 million domains in existence today. Meaning there are twice as many unique historic (deleted or expired and not re-registered currently) domains as there are domains in DNS today.



Interestingly, nobody actually knows the number of unique domains that have ever existed. Only generic Top Level Domains publish daily zone files (lists of domains in their TLD), and even those miss intra-day registrations and deletions, like the ones we commonly see with Phishing campaigns. Then there are the ccTLDs (country-code domains such as .au .de, .jp, etc.) which for the most part do not publish zone files at all so you cannot know all the domains that exist at any point in time in those TLDs. And there are a limited number of ‘dark domains’ that are registered but not provisioned in DNS. The full set of ever-existent domains is the sum of historic information held respectively at all TLD Registries worldwide. But this information does not exist anywhere together, as far as we know.

DomainTools has done a decent job of domain discovery and tracking over our 17 year history, so the one billion number is probably within 10% of the actual number. Regardless, we thought it would be fun to post a few statistics on the domains we’ve seen to-date. And to be clear, we are strictly talking about domains here, different from hostnames, subdomains, “websites” or whatever statistic this article was trying to convey 3 years ago:

  • Not surprisingly, .com has the most historic domains, with nearly 434 million that no longer exist.
  • For domains with at least 1000 current registrations, the gTLD with the highest percentage of deleted domains is .realty with almost 97% of ever-registered domains now deleted.
  • For domains with at least 1000 current registrations, the gTLD with the lowest percentage of deleted domains is .boston with only 0.3% of their 22,100 domains having ever been deleted and not re-registered.
  • From a ccTLD perspective, we have seen over 110 million domains from European countries, over 54 million from Oceanic countries, over 44 million from Asian countries, about 16 million from South American countries and over 12 million from African countries. How about North America? Only about 14 million, and half of that is Canada and Mexico. It’s still a .com world in the U.S.
  • Putting aside the nic.tld required registration for new gTLDs, the top 10 strings that exist in the most TLDs, each with over 700 registrations (ever), are:
    1. amazon
    2. bitcoin
    3. www
    4. whatsapp
    5. blockchain
    6. microsoft
    7. yahoo
    8. mail
    9. oculusrift
    10. google
  • Overall there are nearly 150 strings that have ever been registered in at least 500 TLDs, including fun ones like “iot”, “startup”, “hello”, “cannabis”, “the” and “matt”.

So what does it mean to get to one billion domains? Mostly that there has been a lot of trial and error over the last 25+ years of the modern internet. Even among the 350 million or so currently registered domains, one can make strong arguments that far less than 100 million actually matter. Things like domain tasting, free or nearly free domain promotions, botnet domain generation algorithms, and other unfortunate relics of DNS have driven this number much higher than it would otherwise have been. But if a domain has ever been registered, chances are we’ve seen it somewhere along the way.