OpenAI Updates ChatGPT with GPT 5.5 Instant for Smarter and More Personalized Responses

OpenAI announced on its website that GPT 5.5 Instant is now the default model for ChatGPT, replacing GPT 5.3 Instant. The update delivers smarter and more accurate responses with clearer phrasing and improved personalization.

OpenAI reports that GPT 5.5 Instant produces 52.5 percent fewer hallucinated claims and 37.3 percent fewer inaccurate statements compared to GPT 5.3 Instant on user-flagged prompts. The model performs better in areas such as mathematics, science, and legal or financial reasoning. It also improves analysis of images and decisions about when to use web search.

The new version generates shorter and more direct answers while maintaining a natural tone. It asks fewer unnecessary follow-up questions and avoids overuse of formatting or emojis. OpenAI’s internal tests show notable accuracy gains on benchmarks like AIME 2025 math and GPQA science evaluations.

GPT 5.5 Instant also introduces enhanced personalization by referencing previous chats, files, and connected Gmail accounts when available. A new feature called memory sources shows which context was used to personalize a response, allowing users to delete or adjust stored information. These personalization tools are rolling out first to Plus and Pro users on the web, with mobile support and broader availability planned soon.

GPT 5.3 Instant will remain accessible for paid users for three months through configuration settings before retirement.