3 and 4 Letter .ai Domains for Sale: Short .ai Domain Names

A short .ai domain does two scarce things at once. The .ai ending tells anyone who reads it that this is an artificial intelligence company, the way Character.ai, Perplexity.ai, and You.ai use it, and the short label makes the name easy to say, type from memory, and fit on a logo. Put them together and you get the address an AI brand actually wants: a few letters before the dot and the clearest signal in tech after it. That combination is why short AI domains sit at the top of every founder's wishlist and command the prices they do.

Short names are scarce by math, not opinion. There are only 676 possible two-letter combinations and exactly 17,576 three-letter combinations of the alphabet, and on the major extensions every one of them was claimed years ago. Four-letter and five-letter names go fast for the same reason. New gold gets mined every year, but no one can create a new three-letter string, so the supply of short, pronounceable names only shrinks as more companies launch. When a clean short .ai name is available, it is genuinely rare, and that scarcity is the floor under its value.

The .ai aftermarket has turned that scarcity into real money. Industry sales data shows .ai set records through 2025 as AI funding poured in, with premium names trading from five figures into the millions. Reported sales like Fin.ai and You.ai changing hands in the six and seven figures show what a short, exact-match .ai is worth to a funded team, and short labels carry the highest premium because they are the hardest to find and the easiest to brand. A name that reads as a real word or a tight invented brand, in three to five letters, is the most contested inventory in the category.

There is a practical reason founders pay up front rather than settle. The .ai registry requires a minimum two-year registration and renews at roughly 100 dollars or more per year, so a .ai is already a deliberate, paid choice rather than a throwaway. A startup that picks a long, hyphenated, or misspelled name to save money usually pays for it later in a rebrand, a lost trademark fight, or a competitor sitting on the exact-match address right when funding lands. Locking in a short, ownable .ai before the round, before the launch, and before a rival grabs it is the cheaper path. Compare your options across 3 letter domains, 4 letter domains, and 5 letter domains to see where the value sits for your name.