The guide
Choosing a Reddit username you won't regret
Your username is permanent on Reddit and it sits next to every post and comment you make. A minute of thought now saves you from starting a new account later.
Reddit username rules
Reddit usernames are 3 to 20 characters long and can only use letters, numbers, underscores and hyphens. They are not case sensitive, and a name that was ever used, even by a deleted account, can never be registered again. That is why short dictionary words are almost all taken: combinations of two words, or a word and a number, are what is left.
Can you change your Reddit username?
No. According to Reddit's help center, once a username is finalized it cannot be changed at all, capitalization included. What you can change is your display name, under Settings > Profile on the web or Edit on your profile in the app. If you need a different u/name, the only option is a new account; Reddit allows you to have more than one.
Usernames for brands and founders
If you plan to talk about your product on Reddit, use a username that makes the connection obvious. Most subreddits that allow self-promotion at all require you to disclose your affiliation, and a name like "Sam_from_Acme" does part of that work for you. Personal founder accounts usually earn more trust than a bare brand account, because people prefer replying to a person.
Whatever the name, the account still needs history before it can post freely: many subreddits filter new or low-karma accounts automatically. Check how an account looks to moderators with the free Reddit Account Analyzer.
Anonymous and throwaway accounts
For an account that should not be linked to you, avoid your real name, your usual online handle, your city and your birth year. Random two-word names with a few digits are the safest pattern. Remember that using alternate accounts to upvote yourself or dodge bans breaks Reddit's rules and gets every linked account suspended.