OpenAI announced that Deep Research based on ChatGPT o4-mini will be available to all Free users, while everyone else will get higher limits.

ChatGPT Deep Research is now free for all users, however, it's powered by the smaller o4-mini model and limited to 5 tasks per month.

Depending on your ChatGPT plan, there are limits to how often you can use Deep Research: Plus and team users can use the full version 10 times and the lightweight version 15 times each month. Once a user uses up their full-version limit, ChatGPT will automatically switch to the lighter version, so you can keep going without being cut off.