OpenAI has officially launched GPT-5.1, the next iteration of its GPT-5 series, bringing major improvements in reasoning, conversational flow, and personalization. The update introduces two new models — GPT-5.1 Instant and GPT-5.1 Thinking — designed to make ChatGPT more adaptive, intuitive, and intelligent across a range of tasks.
GPT-5.1 Instant: Faster, Friendlier, and Smarter
GPT-5.1 Instant is the new default model for most users. It’s built for speed and natural conversation, with responses that sound warmer and more human. OpenAI says instruction-following has been significantly improved, making it better at understanding nuanced user prompts.
The model also features adaptive reasoning, which lets it dynamically decide how much processing power to spend on each question. That means it can think longer for tough problems while still staying fast for quick queries. Internal benchmarks reportedly show gains in math and coding tests, including AIME 2025 and Codeforces challenges.
GPT-5.1 Thinking: Deep Reasoning, On-Demand
For complex reasoning tasks, GPT-5.1 Thinking is built to handle deeper, multi-step logic. It adjusts its speed depending on complexity — delivering near-instant answers for simple tasks and taking extra time when precision matters most.
Compared with GPT-5 Thinking, the new version is twice as fast on easy questions and more deliberate on hard ones, producing responses that are clearer and more human-like. The model’s tone has also been fine-tuned to sound empathetic and approachable, even in technical contexts.
What’s New in GPT-5.1
The update isn’t just about raw performance. OpenAI has also introduced a suite of personalization and usability enhancements to give users more control over how ChatGPT behaves:
- Adaptive Model Routing: Automatically chooses the best model (Instant or Thinking) for each query.
- Six Chat Styles: Users can switch between Default, Friendly, Efficient, Professional, Candid, and Quirky tones.
- Legacy Styles Retained: Popular modes like Cynical and Nerdy are still available.
- Fine-Tuning Controls: Adjust conciseness, warmth, scannability, and even emoji usage.
- Proactive Suggestions: ChatGPT can now suggest tone or style changes mid-conversation.
- Instant Effect: Updates to personal settings apply immediately across all chats.
- Improved Custom Instructions: More precise control over tone, phrasing, and behavior.
Availability and Rollout
GPT-5.1 Instant and GPT-5.1 Thinking are now rolling out to paid ChatGPT users — including Pro, Plus, Go, Business, Enterprise, and Education — with free and logged-out users to follow in the coming weeks.
- Enterprise and Education plans get seven-day early access (off by default).
- GPT-5.1 will eventually become the default ChatGPT model for everyone.
- Legacy GPT-5 models will remain accessible to paid users for three months.
- Both new models will also be available through the API as gpt-5.1-chat-latest and gpt-5.1, supporting adaptive reasoning.
Looking Ahead
OpenAI says GPT-5.1 is a “step forward in intelligence and usability,” with more upgrades planned to improve reasoning and personalization. The company aims to make ChatGPT not just a conversational tool, but a personalized digital collaborator that understands your preferences — and evolves with you.