ChatGPT just got smarter! OpenAI launches GPT 5.1 — see what's new

Altman posted on X, "GPT-5.1 is out! It's a nice upgrade. I particularly like the improvements in instruction following, and the adaptive thinking. The intelligence and style improvements are good too."

What is GPT‑5.1?

GPT‑5.1 is an upgrade to the GPT‑5 series.

It launches with two main variants:

• GPT‑5.1 Instant – designed for fast responses, more conversational tone.
• GPT‑5.1 Thinking – designed for more complex reasoning tasks; takes longer when needed, gives more in‑depth explanations.

It is rolling out first to paid tiers of ChatGPT (Plus, Pro, Business) and will gradually become available to free tier users.

"We heard clearly from users that great AI should not only be smart, but also enjoyable to talk to," an OpenAI statement reads.

Key improvements compared to GPT‑5

Here are some of the major enhancements in GPT‑5.1:

Warmer, more conversational style: The Instant variant emphasises a more human‑like tone and better instruction following.

Better instruction‑following: GPT‑5.1 is more reliable in adhering to constraints like 'only six words', or 'answer in bullet points' and more accurate in interpreting what you mean.

Adaptive reasoning / thinking time: The system can decide when a prompt needs deeper thought (i.e., switch to “Thinking” mode) and when it can respond quickly (Instant).

More customization of tone / personality: Users can choose style presets (e.g., Professional, Friendly, Quirky) and also adjust tone, emoji frequency, etc.

Clearer explanations, less jargon: Particularly in Thinking mode, the explanations are meant to be more accessible (less technical jargon) and better for complex tasks.