There are exactly 4,548,848,190,855,552 possible 10-character domain names — four quadrillion five hundred forty-eight trillion eight hundred forty-eight billion one hundred ninety million eight hundred fifty-five thousand five hundred fifty-two. If each domain name were one millimeter long, laid end to end they would stretch from the Sun to Neptune and back — over 30 times. The ten-character namespace is planetary in scale.
Using letters only (a–z), there are 141,167,095,653,376 possible domains. Laid end to end as millimeter marks, these domains would span a round trip to Mars. Even letter-only combinations are astronomically large at this length.
Allowing both letters and digits (a–z, 0–9) creates 3,656,158,440,062,976 combinations. More combinations than the distance in millimeters from Earth to Pluto. No TLD will ever come close to saturating ten-character alphanumeric domains.
Here's how saturated each TLD is at this length.
quadrillion valid combinations
all valid 10-character domain labels (a–z, 0–9, hyphens)
| # | TLD | Registered | % Full (Alpha) |
|---|---|---|---|
| 1 | .com | 6,874,208 | <0.01% |
At 10 characters, the domain namespace becomes vast — 141,167,095,653,376 possible alphabetic combinations. Even the most popular TLDs have significant availability at this length. The challenge shifts from scarcity to finding memorable, meaningful names.
Longer domains are often full words or multi-word combinations. While they lack the premium cachet of short domains, they offer excellent opportunities for keyword-rich, descriptive domain 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)
2610 = 141,167,095,653,376
Only the 26 lowercase letters. The simplest calculation — each position has 26 choices, so 10 positions gives 2610.
Alphanumeric (a–z, 0–9)
3610 = 3,656,158,440,062,976
Letters plus digits. Each position has 36 choices. Domain names are case-insensitive, so uppercase and lowercase are equivalent.
All Valid Labels
4,548,848,190,855,552 total
Includes hyphens, but with restrictions. The total is not simply 3710 because hyphens have placement rules.
| Character Set | Characters | Formula | 10-Char Combinations |
|---|---|---|---|
| Alphabetic | a–z (26) | 2610 | 141,167,095,653,376 |
| Alphanumeric | a–z, 0–9 (36) | 3610 | 3,656,158,440,062,976 |
| All Valid Labels |
trillion alphabetic
2610 using a–z
quadrillion alphanumeric
3610 with digits 0–9
saturation
across 50 TLDs
.com registered
<0.01% of total
| 2 | .net | 1,005,482 | <0.01% |
| 3 | .org | 853,398 | <0.01% |
| 4 | .xyz | 507,447 | <0.01% |
| 5 | .shop | 329,704 | <0.01% |
| 6 | .info | 316,331 | <0.01% |
| 7 | .online | 292,218 | <0.01% |
| 8 | .top | 257,755 | <0.01% |
| 9 | .ch | 209,362 | <0.01% |
| 10 | .store | 198,342 | <0.01% |
| 11 | .site | 146,757 | <0.01% |
| 12 | .pro | 129,658 | <0.01% |
| 13 | .se | 121,733 | <0.01% |
| 14 | .vip | 98,393 | <0.01% |
| 15 | .app | 87,387 | <0.01% |
| 16 | .skin | 87,084 | <0.01% |
| 17 | .biz | 86,399 | <0.01% |
| 18 | .sbs | 57,829 | <0.01% |
| 19 | .space | 44,132 | <0.01% |
| 20 | .run | 44,059 | <0.01% |
| 21 | .world | 39,988 | <0.01% |
| 22 | .club | 39,273 | <0.01% |
| 23 | .click | 38,853 | <0.01% |
| 24 | .dev | 38,549 | <0.01% |
| 25 | .tech | 38,224 | <0.01% |
| 26 | .live | 38,051 | <0.01% |
| 27 | .cloud | 36,489 | <0.01% |
| 28 | .cfd | 31,959 | <0.01% |
| 29 | .art | 22,766 | <0.01% |
| 30 | .life | 22,637 | <0.01% |
| 31 | .today | 21,567 | <0.01% |
| 32 | .bond | 19,628 | <0.01% |
| 33 | .cyou | 18,624 | <0.01% |
| 34 | .blog | 18,431 | <0.01% |
| 35 | .icu | 17,485 | <0.01% |
| 36 | .website | 16,376 | <0.01% |
| 37 | .hair | 16,248 | <0.01% |
| 38 | .digital | 16,246 | <0.01% |
| 39 | .nu | 16,120 | <0.01% |
| 40 | .asia | 15,427 | <0.01% |
| 41 | .work | 15,303 | <0.01% |
| 42 | .fun | 14,480 | <0.01% |
| 43 | .mobi | 12,496 | <0.01% |
| 44 | .studio | 11,467 | <0.01% |
| 45 | .lol | 10,523 | <0.01% |
| 46 | .forum | 10,264 | <0.01% |
| 47 | .one | 9,989 | <0.01% |
| 48 | .link | 9,322 | <0.01% |
| 49 | .rest | 9,138 | <0.01% |
| 50 | .buzz | 8,771 | <0.01% |
| a–z, 0–9, hyphen (37) |
| With placement rules |
| 4,548,848,190,855,552 |
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 × 37^8 × 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.