OpenAI Launches GPT-5.5 Instant As New Default ChatGPT Model
OpenAI has introduced GPT-5.5 Instant as the new default model for ChatGPT, replacing GPT-5.3 Instant. The company said the updated model aims to reduce hallucinations in sensitive fields such as law, medicine and finance while maintaining fast response speeds.
The launch follows the broader release of the GPT-5.5 series last month, which brought improvements in coding, reasoning and knowledge-based tasks.
GPT-5.5 Instant Shows Benchmark Gains
According to OpenAI, GPT-5.5 Instant delivers stronger performance across several technical benchmarks.
The model scored 81.2 points on the AIME 2025 mathematics benchmark, up from 65.4 points achieved by the previous version. OpenAI also reported improvements in the MMMU-Pro multimodal reasoning benchmark, where the model scored 76 compared with 69.2 previously.
The results indicate stronger performance in solving complex mathematical problems, logical reasoning tasks and multimedia-related queries.
OpenAI said the model was designed to provide more reliable responses in areas where factual accuracy is especially important.
Improved Memory And Search Features Added
One of the most significant updates involves enhanced contextual understanding capabilities.
GPT-5.5 Instant can now use integrated search tools that reference previous conversations, uploaded files and Gmail data to deliver more personalised responses.
The feature will initially roll out to Plus and Pro subscribers through the web version of ChatGPT. OpenAI said support for the mobile application will arrive shortly afterwards.
The company also plans to expand the functionality to Free, Go Business and enterprise users over the coming weeks.
OpenAI Expands Transparency Features
OpenAI has also introduced new transparency tools across ChatGPT models.
Users will now be able to view memory source information that shows where the AI retrieved contextual details used in responses. The update also allows users to remove or correct outdated information stored by the system.
According to OpenAI, memory details remain private and are not shared when users send conversations to others.
The company said these changes are designed to improve trust, user control and response accuracy while supporting more advanced AI interactions.
Focus Remains On Reliability And Speed
The launch of GPT-5.5 Instant reflects OpenAI’s continued focus on balancing speed with reliability.
Reducing hallucinations has become a major priority across the artificial intelligence industry, particularly in sectors involving legal, medical and financial information.
The latest update also highlights growing competition among AI developers to improve reasoning abilities, contextual awareness and multimodal performance without sacrificing efficiency.
OpenAI said GPT-5.5 Instant will now serve as the standard ChatGPT experience for users moving forward.