OpenAI introduces ChatGPT 5.1: what’s new

OpenAI has officially unveiled its new GPT-5.1 family of models, according to the company’s announcement.

The update brings two versions — GPT-5.1 Instant and GPT-5.1 Thinking. The Instant model is faster and more responsive, while the Thinking version handles complex reasoning with greater accuracy and consistency.

ChatGPT has also learned better manners. OpenAI added new customization tools that let users adjust tone, style, and personality. Available response styles now include:

• Default
• Friendly
• Efficient
• Professional
• Candid
• Quirky

Users can fine-tune traits such as brevity, warmth, or emoji use directly in personalization settings. ChatGPT can even prompt users to update these preferences mid-conversation if it detects a consistent tone or format in their requests.

The GPT-5.1 Instant model feels more conversational and empathetic, while following instructions more precisely. Its standout feature is adaptive reasoning — the ability to decide when to “think” before replying or respond immediately, depending on the complexity of the task.

The GPT-5.1 Thinking model, in turn, allocates more time to difficult problems but replies faster to simple ones. Its responses are now more concrete and concise, with fewer vague or filler terms.

The rollout has already begun for paid users and will gradually expand to all ChatGPT accounts over the coming days. Previous GPT-5 models will remain available to Plus subscribers for the next three months.