Yesterday, OpenAI upgraded its GPT 5 series with the release of GPT 5.1, which includes two models: GPT 5.1 Instant and GPT 5.1 Thinking.
GPT 5.1 Instant
GPT 5.1 Instant now responds in a warmer and more conversational tone. The instruction following is also improved, so the model more reliably answers the question you actually asked. For the first time, GPT 5.1 Instant can use adaptive reasoning to decide when to think before responding to more challenging questions, resulting in more thorough and accurate answers, while still responding quickly.
GPT 5.1 Thinking
It adapts its thinking time more precisely to the question, spending more time on complex problems while responding more quickly to simpler ones. The model will now provide more thorough answers for difficult requests and less waiting for simpler ones. The responses are also clearer, with less jargon and fewer unidentified terms. The default tone of this model is warmer and more empathetic.
As per OpenAI, answers across GPT-5.1 feel both smarter and more natural in tone. It includes six chat styles: Default, Friendly, Efficient, Professional, Candid, and Quirky options. GPT 5.1 allows adjustments for conciseness,
Availability
GPT 5.1 Instant and Thinking begin rolling out today, starting with Paid (Pro, Plus, Go, Business) users and then to free and logged-out users. Enterprise and Edu plans get a seven-day early-access toggle (off by default). After that window, GPT-5.1 will become the sole default model.
GPT 5.1 Instant and Thinking will be coming to the API later this week. GPT 5.1 Instant will be added as pt-5.1-chat-latest, and GPT-5.1 Thinking will be released as GPT-5.1 in the API, both with adaptive reasoning.
The company has revealed that the GPT-5 Pro model will soon be updated to GPT-5.1 Pro soon while GPT-5 (Instant and Thinking) will remain available in ChatGPT under the legacy models dropdown for paid subscribers for three months, so people have time to compare and adapt at their own pace.
