OpenAI has upgraded its GPT-5 lineup with the launch of GPT-5.1 Instant and GPT-5.1 Thinking, delivering gains in intelligence, clarity and tone. GPT-5.1
Instant, the most widely used model in ChatGPT, is now warmer and more conversational, with improved instruction following and adaptive reasoning that decides when deeper thinking is required. GPT-5.1 Thinking, designed for complex tasks, dynamically adjusts how long it reasons – moving faster on simple prompts and spending more time on harder ones – while producing clearer, less jargon-heavy responses.
Both models show improved performance on coding and reasoning benchmarks. The update also introduces expanded personalization controls, allowing users to select response styles such as Professional, Friendly or Quirky, with more granular tuning rolling out. GPT-5.1 is being phased in as the default model across ChatGPT and the API.
Read more in the OpenAI blog.