There are exactly 2,427,138,432 possible 6-character domain names — two billion four hundred twenty-seven million one hundred thirty-eight thousand four hundred thirty-two. More possible domains than there are grains of sand in a dump truck. At six characters, the namespace starts to feel genuinely vast — yet .com still has surprisingly high saturation.
Using letters only (a–z), there are 308,915,776 possible domains. About as many combinations as the entire population of the United States. A number everyone can picture, and one that is still within reach for a determined registry.
Allowing both letters and digits (a–z, 0–9) creates 2,176,782,336 combinations. Comparable to a third of the world population. Large, but not unimaginable — and new registrations chip away at it every day.
Here's how saturated each TLD is at this length.
billion valid combinations
all valid 6-character domain labels (a–z, 0–9, hyphens)
| # | TLD | Registered | % Full (Alpha) |
|---|---|---|---|
| 1 | .com | 4,292,961 | 1.4% |
Six-character domains sit in a sweet spot between scarcity and availability. With 308,915,776 possible alphabetic combinations, the namespace is large enough that opportunities exist in many TLDs, yet small enough that popular extensions are heavily saturated.
At this length, many real English words, brand names, and dictionary terms are possible. The mix of registered domains typically includes common words, abbreviations, and brandable names.
Domain name labels (the part before the dot) follow strict character rules defined in RFC 5891 and RFC 1035. DNSChkr calculates three tiers of possible combinations for each domain length:
Alphabetic (a–z)
266 = 308,915,776
Only the 26 lowercase letters. The simplest calculation — each position has 26 choices, so 6 positions gives 266.
Alphanumeric (a–z, 0–9)
366 = 2,176,782,336
Letters plus digits. Each position has 36 choices. Domain names are case-insensitive, so uppercase and lowercase are equivalent.
All Valid Labels
2,427,138,432 total
Includes hyphens, but with restrictions. The total is not simply 376 because hyphens have placement rules.
| Character Set | Characters | Formula | 6-Char Combinations |
|---|---|---|---|
| Alphabetic | a–z (26) | 266 | 308,915,776 |
| Alphanumeric | a–z, 0–9 (36) | 366 | 2,176,782,336 |
| All Valid Labels |
million alphabetic
266 using a–z
billion alphanumeric
366 with digits 0–9
saturation
across 50 TLDs
.com registered
1.4% of total
| 2 | .top | 1,780,425 | 0.58% |
| 3 | .net | 805,460 | 0.26% |
| 4 | .info | 616,849 | 0.20% |
| 5 | .org | 605,795 | 0.20% |
| 6 | .xyz | 462,294 | 0.15% |
| 7 | .vip | 451,697 | 0.15% |
| 8 | .shop | 392,043 | 0.13% |
| 9 | .bond | 275,327 | 0.09% |
| 10 | .sbs | 225,787 | 0.07% |
| 11 | .online | 177,951 | 0.06% |
| 12 | .ch | 135,558 | 0.04% |
| 13 | .store | 129,004 | 0.04% |
| 14 | .site | 128,918 | 0.04% |
| 15 | .cfd | 127,612 | 0.04% |
| 16 | .asia | 121,433 | 0.04% |
| 17 | .app | 117,882 | 0.04% |
| 18 | .pro | 103,160 | 0.03% |
| 19 | .se | 97,067 | 0.03% |
| 20 | .lol | 88,812 | 0.03% |
| 21 | .biz | 77,137 | 0.02% |
| 22 | .club | 58,557 | 0.02% |
| 23 | .dev | 58,296 | 0.02% |
| 24 | .mobi | 55,902 | 0.02% |
| 25 | .tech | 55,276 | 0.02% |
| 26 | .cyou | 52,633 | 0.02% |
| 27 | .cloud | 51,786 | 0.02% |
| 28 | .space | 45,583 | 0.01% |
| 29 | .click | 45,186 | 0.01% |
| 30 | .live | 39,697 | 0.01% |
| 31 | .life | 35,706 | 0.01% |
| 32 | .makeup | 34,413 | 0.01% |
| 33 | .icu | 28,620 | 0.01% |
| 34 | .world | 26,616 | 0.01% |
| 35 | .art | 20,668 | 0.01% |
| 36 | .work | 19,886 | 0.01% |
| 37 | .fun | 18,285 | 0.01% |
| 38 | .one | 17,971 | 0.01% |
| 39 | .website | 17,431 | 0.01% |
| 40 | .nu | 16,320 | 0.01% |
| 41 | .yachts | 16,258 | 0.01% |
| 42 | .studio | 15,186 | <0.01% |
| 43 | .digital | 13,952 | <0.01% |
| 44 | .beer | 13,706 | <0.01% |
| 45 | .blog | 13,388 | <0.01% |
| 46 | .bet | 13,128 | <0.01% |
| 47 | .link | 12,261 | <0.01% |
| 48 | .beauty | 10,633 | <0.01% |
| 49 | .autos | 9,838 | <0.01% |
| 50 | .ltd | 8,615 | <0.01% |
| a–z, 0–9, hyphen (37) |
| With placement rules |
| 2,427,138,432 |
Hyphen Placement Rules
xn--example are reserved for internationalized domain names (IDN) under RFC 5891 §4.2.3.1. A hyphen in position 3 and position 4 simultaneously is not permitted in standard registrations.These constraints mean the "all valid" count is less than a simple 36 × 37^4 × 36 calculation — the double-hyphen exclusion at positions 3–4 removes a subset of otherwise valid combinations. All three counts are mathematical constants that never change — only the number of registered domains (shown in the table above) changes daily.