We talked about this update in October… OpenAI is gradually rolling out GPT-5.1, a major update to its text generation technology. This new version aims to make ChatGPT both more capable, more natural in conversation, and more adaptable to each user’s preferences. Two main variants, GPT-5.1 Instant and GPT-5.1 Thinking, mark another step toward balancing speed, accuracy, and personalization.
GPT-5.1 Instant: a faster and more conversational model
The GPT-5.1 Instant model, the most widely used in ChatGPT, has been redesigned to offer smoother and more engaging interactions. Its communication style is now more natural while maintaining clarity and usefulness. This model also features a clear improvement in instruction following, allowing it to respond more accurately to the actual question asked.
A key technical innovation is its ability to perform adaptive reasoning. GPT-5.1 Instant can assess the complexity of a question before answering, enabling it to deliver more precise responses to complex requests without compromising speed for simpler ones. This improvement is reflected in higher scores on math and programming benchmarks such as AIME 2025 and Codeforces.
GPT-5.1 Thinking: more precise reasoning and clearer answers
The second model, GPT-5.1 Thinking, stands out for its refined management of thinking time. It dedicates more resources to complex problems while responding faster to straightforward queries. This makes interactions more efficient and enjoyable in daily use.
The responses generated by GPT-5.1 Thinking are also designed to be more accessible, with less jargon and clearer explanations. The goal is to make technical concepts easier to understand, particularly in professional or educational contexts. This model also adopts a warmer and more empathetic tone by default, enhancing its overall approachability.
ChatGPT tone and style customization options
Alongside the technical improvements, OpenAI is placing greater emphasis on tone personalization within ChatGPT. Users can now choose from several response styles such as “Default”, “Friendly”, “Efficient”, “Professional”, “Candid”, and “Quirky”. These presets are designed to align with the various ways people prefer to interact with the tool.
For those seeking more granular control, OpenAI is experimenting with the ability to fine-tune specific response traits, such as conciseness, warmth, or emoji usage. ChatGPT can also proactively suggest tone adjustments during conversations, ensuring a more consistent and tailored experience without requiring users to open settings manually.
Gradual rollout and transition to GPT-5.1
The rollout of GPT-5.1 begins with paying users under the Pro, Plus, Go, and Business plans, before expanding to free accounts. Earlier GPT-5 versions will remain available for a three-month transition period, allowing users to compare and adapt at their own pace.
Both GPT-5.1 Instant and GPT-5.1 Thinking will soon be accessible through the OpenAI API, under the names “gpt-5.1-chat-latest” and “GPT-5.1” respectively. This ensures a smooth adoption process and full compatibility with existing integrations.
Toward a smoother and more personalized ChatGPT experience
With this update, OpenAI continues its pursuit of a smarter, more natural, and more adaptable ChatGPT. GPT-5.1 is not just a performance improvement—it represents a step toward aligning artificial intelligence with each user’s preferred style and tone. This evolution highlights OpenAI’s goal of making digital assistants more intuitive and genuinely customizable.
Source: https://openai.com/index/gpt-5-1/