OpenAI launches GPT 5.1 models with faster, "warmer" and more conversational variants

OpenAI has introduced GPT 5.1 as the new default model for paid ChatGPT users, bringing two variants: Instant and Thinking. Instant focuses on faster instruction following with a "warmer" and more conversational personality, plus adaptive reasoning that lets it decide when deeper thinking is needed for complex questions.

The Thinking variant improves advanced reasoning, solves simple tasks more quickly, and maintains focus on complex ones. It now uses simpler language and adopts a warmer, more empathetic tone. A new Auto mode routes prompts to Instant or Thinking depending on the task. Personalization also now includes new tone options such as Professional, Candid, and Quirky, plus updates to the Default, Friendly, and Efficient settings. ChatGPT may also suggest adjusting your tone if it detects repeated requests for a different style.

GPT 5.1 is rolling out first to Pro, Plus, Go, and Business users, with free accounts to follow, and GPT 5 models will remain available for three months under the legacy dropdown so users can compare and transition at their own pace. Availability may vary since these updates are being released gradually.