Gamertag and username rules by platform: length, characters and changes

Why every platform has different rules

A player name does two jobs. It identifies you uniquely to the system and, at the same time, is what other players read on screen.

Some platforms separate the two. Discord has the username, unique and restricted, and the display name, which is free-form. Roblox has the username, which costs Robux to change, and the display name, which is free.

Others merge everything into one name and control changes through price, waiting time, or both. Understanding this split explains almost every difference in the rules below.

The comparison table (checked 2 Nov 2026)

Each cell comes from an official page listed in the sources. Where the official page does not provide the data, the cell says “not confirmed” instead of repeating what circulates on blogs. The one exception is the Roblox username length and characters, which the help page does not list: they come from the error messages of Roblox’s own name validation endpoint, tested on 2 November 2026.

Three patterns in the table

The first pattern is a unique identifier plus a display name. On Discord and Roblox the identifier is rigid and the nickname is free, so you can have any style on screen without touching the account record.

The second pattern is the numeric suffix. In Microsoft’s documentation a modern gamertag has up to 12 characters and receives a suffix after “#”, normally 4 digits when the name is 11 characters or fewer. The total, including the “#”, never exceeds 16.

The third pattern is the cost of a change. Sony says the first online ID change is free and later ones are charged. Roblox charges Robux for a username change, but a display name change is free.

Two examples tested against the table

Example 1: “Shadow.Wolf_99”. On Discord it becomes “shadow.wolf_99” (13 characters, only a-z, 0-9, “_” and “.”), so it is accepted. On Roblox it is rejected, because the period is not allowed; swapping the period for an underscore fixes it, since one underscore is allowed.

Example 2: “Xx_DarkLord_Slayer_xX” has 21 characters and three underscores. It breaks Roblox (maximum 20 and a single underscore), the Xbox modern gamertag (12) and the Minecraft Java profile (16). Only Discord would accept it, in lowercase.

• Use 3 to 12 characters: it fits every length rule confirmed here.
• Stick to letters and digits, with at most one underscore.
• Avoid periods: Roblox does not accept them.
• Check that the name stays readable in lowercase, which is how Discord shows it.
• Do not include a real name, age or school. This matters most for minors.

How to pick and test a name

Start with one or two words that describe the style you want and generate variations. The nickname generator brings symbols and categories, the Roblox name generator respects the 3 to 20 character rule and the Minecraft name generator helps you avoid the obvious.

Then test the name on each platform before paying for any change. If the name is taken, add a number or swap a word rather than forcing characters the platform rejects.

Roblox players may also like the guides on Asset ID, Universe ID and Place ID and on Robux and DevEx.