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.

Though not as powerful as the full Deep Research, the new lighter version is available to all ChatGPT users, and it'll automatically kick in for paid subscribers once they hit their limit - no extra step required.