ChatGPT: What's free in 2026 and what isn't?

As of August 2026, OpenAI limits free accounts to using just one of its models: GPT-5.6 Luna. Luna is the smallest of the company's recently released GPT-5.6 family of large language models. Access to the company's other models, including GPT-5.6 Terra and Sol, requires a subscription or paying for API pricing. Free accounts are also limited to just a single reasoning mode. Tapping the Think button will prompt ChatGPT to take additional time to generate a response; there's no slider like you'll find if you pay for a subscription.