OpenAI says ChatGPT can now estimate whether you are under 18, even without asking you. The company has detailed how its age prediction system works. A dedicated AI model studies how an account is used. It looks at behavioral and account-level signals: the topics you discuss, the times you use ChatGPT, how usage patterns change over time, and how long the account has existed. It does not replace the date of birth you gave at sign-up. It is an extra check on top. If the system decides an account belongs to someone under 18, it switches the account to the ChatGPT for Teens experience. Some features and interactions are restricted there, though users can still learn, create and ask questions. You can see your age category under Settings, then Account, then Age. The system is not without controversy. Common Sense Media rated ChatGPT for Teens an “unacceptable risk” after tests found missing parental alerts and failing crisis referrals. OpenAI strongly disputed the testing method. The age checks also matter for OpenAI’s ad business, since the company says it will not show ads to minors.