The length of a ban in Roblox can vary depending on the severity of the offense committed by a user. Temporary bans can range from a few days to several weeks or months. Permanent bans result in a permanent termination of the user's account. The length of a ban is typically determined by Roblox's moderation team based on their assessment of the violation. For the most accurate and up-to-date information, it's best to refer to Roblox's official documentation or reach out to their support team.