OpenAI Improves GPT-5.6 Sol, Expands ChatGPT Free Tier With Unlimited Text Chats

OpenAI is improving GPT-5.6 Sol in ChatGPT while expanding access for users on its Free and Go tiers. The update removes text chat rate limits, subject to abuse guardrails, adds a new Think button for harder questions, and introduces a more capable GPT-5.6 Sol experience for Plus and Pro subscribers.



The default ChatGPT model for Free and Go users will become GPT-5.6 Luna this week, following the introduction of OpenAI's GPT-5.6 model family in June. The company says an internal evaluation found factual errors were 62 percent less common with GPT-5.6 Luna than GPT-5.5 Instant on financial, medical, and legal prompts requiring factual detail. A new Think button will let Free and Go users give Luna more time to work through complex requests. Starting next week, those users will also get unlimited text chats, while limits will continue to apply to file uploads, images, voice chats, image generation, and other tools.


For Plus and Pro subscribers, OpenAI is rolling out a new version of GPT-5.6 Sol tuned for everyday ChatGPT use, including quick questions, web searches, planning, research, advice, writing, and complex decisions. This version is separate from the GPT-5.6 Sol model used by Codex and ChatGPT Work, which remains unchanged. The company says the upgraded model delivers more focused answers and adapts its level of detail to each question. Factual errors were also 68 percent less common than with GPT-5.5 Instant in the same internal evaluation. Plus and Pro users can also use a new thinking slider to choose how much reasoning ChatGPT applies to each response, replacing separate Instant and Thinking modes with a single adjustable experience.

According to OpenAI, one billion people now use ChatGPT each week. The upgraded GPT-5.6 Sol model and thinking slider are available to Plus and Pro subscribers starting today. GPT-5.6 Luna rolls out to Free and Go users this week, with unlimited text chats and the new Think button following next week. The changes are rolling out across ChatGPT on the web, mobile, and desktop.