New usernames have two basic requirements:
- They must be at least five characters long and start with a letter
- Only letters and numbers can be used; no special characters, spaces nor symbols
All usernames at Khan Academy are unique. If you try to pick one that is already in use, that username will be rejected. Try a new one!
Moreover, we strongly encourage that you do not use real names or any other information that could be used to identify someone when creating a username or background biography, or in general when posting questions or answers.