OpenAI's Instant model, the lightweight option available to everyday users, just got an upgrade.

On Tuesday, OpenAI launched GPT-5.5 Instant, which was updated to be more reliable, with the company claiming it boasts “significant improvements in factuality across the board.” This claim is particularly notable given that it is the default model for its hundreds of millions of daily users.

Benchmark performance shows that GPT-5.5 Instant outperforms GPT-5.3 Instant, the model currently used in ChatGPT, across multimodal reasoning, document parsing, and science and math evaluations. In everyday performance, OpenAI says the updates mean that users experience:

• Less hallucinations: GPT-5.5 Instant produces 52.5% fewer hallucinated claims than GPT-5.3 Instant on high-stakes prompts in areas like medicine, law, and finance and inaccurate claim reduction by 37.3% on challenging conversations users had flagged for factual errors
• More capable: The model is generally smarter and more capable across photo and image models, STEM questions, and choosing when to fetch information from the web
• Tighter responses: More to the point responses that don’t lose substance
• More personalization: It is more effective at using context from either past chats or connected files and Gmail by being faster at searching past conversations. This is rolling out to Plus and Pro users on the web, and coming soon to mobile. It will expand to more plans in the coming week

OpenAI also introduced memory sources across all ChatGPT models, which give users the ability to see the context used to personalize their responses and then delete or correct it if something is outdated or not wanted to be cited. Essentially, it's giving users more control of how their past chats are used and referenced.

The memory sources feature is rolling out to all consumer plans on the web and soon on mobile. GPT-5.5 Instant is rolling out to all ChatGPT users, replacing GPT-5.3 Instant as the default model, while paid users can still access GPT-5.3 Instant for three months before being retired. It is also available in the API as “chat-latest.”

Our Deeper View

As OpenAI mentioned in the release, because it is a model accessed by hundreds of millions of people every day, even the slightest upgrade is significant. That is specifically true when it comes to improving accuracy and reducing hallucinations. While it is extremely difficult to completely eradicate that issue, since AI models are not actually thinking but rather referencing past data to make predictions based on patterns, any reduction is valuable, as the risk of spreading inaccurate information is significant.