Two Ways to Use This
Switch to "Check a name" if you've already got something in mind, type it in and it checks Roblox directly for whether it's taken. Or flip to "Generate ideas", drop in a word you like, and it spins up a handful of variations and checks all of them at once.
How the Generator Builds Names
It takes your word and tries a few common patterns people actually use, adding numbers, tacking on "Gaming" or "YT", wrapping it in "The" or "Pro", that kind of thing. Every single one gets checked live, so what you see marked open is genuinely open right now.
Why Short Words Run Out Fast
Roblox has hundreds of millions of accounts, so anything short and common gets snapped up early. A plain word with no number attached is the hardest to land, adding a random number or a suffix usually opens things up a lot.
Roblox's Username Rules
Names run 3 to 20 characters, letters, numbers, and underscores only. Roblox also blocks certain words and patterns outright, and a username generally can't start or end with an underscore. If a name fails here it won't necessarily be rejected on Roblox for the same reason, those are two separate checks.