OpenAI gives free ChatGPT users unlimited text chats via GPT-5.6 Luna

OpenAI announced today that it is eliminating caps on text-based conversations for all ChatGPT users, a move that comes as the platform surpassed 1 billion weekly users. The experience is powered by the newly launched GPT-5.6 Luna, which becomes the default model for Free and Go users, replacing GPT-5.5. These users also gain a 'Think' button that enables higher reasoning power for complex questions, though separate limits remain for files, images, voice, and image generation.

Plus and Pro subscribers receive a different upgrade: access to an enhanced GPT-5.6 Sol model optimized for quick, everyday tasks like research, planning, writing, and decision-making. This version delivers more compact and robust answers, and is distinct from the GPT-5.6 Sol used in Codex and Work. Plus/Pro users also get a new thinking slider to control how much effort the model invests per query. OpenAI's internal evaluations show factual errors are 62% less common with GPT-5.6 Luna and 68% less common with GPT-5.6 Sol compared to GPT-5.5-Instant. The upgraded Sol is available today, while free-tier changes roll out this week, with unlimited text chats and the Think button arriving next week.