Every Roblox account has two names. The username - the one you picked, the one that can be changed for 1,000 Robux - and the user ID: a plain number, assigned when the account was created, that never changes no matter how many times the username does. Roblox's own systems run on the number. Sooner or later a tool, a group, or a trade verification will ask you for it, so here's where it lives.
On the website (the ten-second way)
Log in at roblox.com in any browser and open your profile - click your avatar or username. Now look at the address bar. The URL contains your user ID in plain sight:
roblox.com/users/123456789/profile
The number between /users/ and /profile is your user ID. That's the whole trick. It works for any account, not just yours - open anyone's profile and their ID is in the same spot, which is exactly how inventory and value tools resolve a username into the account they actually look up.
In the app
The mobile and tablet apps don't show the URL, so take the long way: open your profile, tap the share icon, and copy the profile link - then read the number out of the link you copied. If the app version you're on buries the share option, the fallback always works: log in through the phone's browser instead and use the address-bar method above.
Why the number matters more than the name
Roblox treats usernames as display labels and the ID as the real identity. That has three practical consequences worth knowing:
- Username changes don't break anything. Friends lists, inventories, group memberships, badges - all keyed to the ID. Someone who changes their name is the same account with the same number, which is also how you can confirm whether "the same person" really is: compare the number, not the name.
- Old usernames get recycled. A name someone abandons can eventually be registered by a stranger. If you're re-adding an old friend or checking whether a trader is the person you dealt with last year, the ID is the only reliable check - a rename is cheap; a new ID is impossible.
- Tools and APIs want the ID. Fan sites, group-management tools, and stat lookups mostly convert your username to the ID as their first step. Handing them the number directly just skips a lookup.
What's safe to share (and what never is)
Your user ID is public information - it's visible in the URL of your profile to anyone on the internet, so sharing it costs you nothing beyond what your public profile already shows. There is no setting to hide it and no need for one; knowing your number lets someone look at your public profile and nothing more.
What it does not do is unlock anything. Nobody can enter your account with a user ID, and no legitimate service will ever ask for your password or a verification code "to confirm your user ID" - that request pattern is a scam, full stop. The rule that covers every case: the number is public, the credentials are not, and anyone trying to blur that line is telling you who they are. If you've already given more than the number to someone who asked, secure the account now and treat it as a close call rather than a catastrophe.
The quick reference
Website: profile URL, number between /users/ and /profile. App: share your profile, read the number from the copied link. It never changes, it's safe to share, and it's the answer to "how do I prove I'm the same account after a rename" - the one identity question in Roblox with a genuinely clean answer.