Daily Usage Limits Explained: ChatGPT’s o3, o4-mini, and o4-mini-high Models

In April 2024, OpenAI introduced a new generation of models known as the o‑series , including o3 , o4‑mini , and later o4‑mini‑high , aiming to deliver faster performance and stronger reasoning at a lower cost. These models were gradually rolled out to ChatGPT Plus, Team, and Pro users, as well as to developers through the OpenAI API.

However, with these new capabilities come varying usage limits depending on subscription tiers.This article explains the current usage policies for the o‑series models, how to access them, how to verify which model you're using, and what to expect from OpenAI next as it continues expanding its model ecosystem.

Comparison Table: Daily Usage Limits for ChatGPT's Latest Models

o-series models are unavailable to free users but accessible to paid users with varying limits. Plus/Team users have daily or weekly caps, Pro users get near-unlimited access, and API users face only rate limits.

How to Activate ChatGPT o3 or o4-mini

Step 1: Confirm Your Plan

Make sure you're on a Plus, Team, or Enterprise plan. Free-tier users currently cannot select o3 or o4‑mini.

Step 2: Open Model Selector

Go to the ChatGPT website , start a new chat. Then click the model selector in the top‑left corner and choose the latest model you'd like to use.

How to Verify If You're Using an o-Series Model

Method 1: Check the Model Label

Look at the top-left corner of the chat window---you'll see a label such as "o3", "o4-mini", or "o4-mini-high." This label clearly indicates which specific model is responding in your current conversation.

Method 2: By the "Thinking..." Interaction Pattern

When an o‑series model (like o3 or o4‑mini) is generating a response in ChatGPT, you'll often notice a distinct interaction pattern: instead of immediately streaming text like GPT‑3.5 or GPT‑4, it will first display a brief "Thinking..." animation ---usually shown as animated dots or a subtle pulse.

After the model replies, a "Thought for ⟨n⟩ seconds" message appears just below the response, indicating how long it spent reasoning before answering.This behavior is unique to o‑series models.

Method 3: Hover Over the Regenerate Button

You can also verify the model used in a specific response by hovering over the regenerate button below the message.This is a quick and reliable way to confirm the model, even after the chat has progressed.

What's Next for ChatGPT

1. o3-pro Coming Soon

OpenAI plans to release o3-pro in the coming weeks with full tool support. For now, Pro users can continue to access o1-pro.

2. Expanded Developer Access

Developers can now use o3 and o4-mini through the Chat Completions API and the new Responses API. These models support advanced features like reasoning summaries and preserved tokens around function calls. In the near future , integrated tools such as web browsing, file search, and code interpreter will also be supported within these models, enhancing their ability to handle complex tasks.

3. Unified Model Direction

OpenAI is bringing together the reasoning strength of the o-series with the conversational and tool-using abilities of the GPT-series . This convergence will lead to future models that can engage in seamless, natural conversations while proactively using tools and solving more complex problems.

[Bonus Tip] Enhance AI-Generated Text with Tenorshare AI Humanizer

While ChatGPT's o-series models are powerful, their responses can still sound overly robotic or detectable as AI-generated, especially in sensitive use cases like academic writing, content creation, or job applications.

That's where Tenorshare AI Humanizer comes in. It helps transform AI-generated text into more natural, human-like language by adjusting tone, structure, and expression, making your content more authentic and harder to flag by AI detectors. Whether you're polishing ChatGPT responses or bypassing detection tools, it's a smart companion for AI-assisted writing.

Conclusion

OpenAI's o-series models( o3 , o4-mini , and o4-mini-high ) offer faster, smarter, and more efficient performance for both ChatGPT users and developers. However, each model comes with different usage limits depending on your plan.

To make the most of your AI-generated content---especially when you want it to sound more natural and human-like---consider using our humanize AI text tool . It helps refine tone, improve readability, and reduce the chance of detection by AI content filters, making it a perfect companion for writing with ChatGPT.

FAQs

Can free users access o3 or o4-mini models in ChatGPT?

No, o-series models like o3, o4-mini, and o4-mini-high are currently only available to Plus, Team, Enterprise, or Pro users. Free-tier accounts cannot use these models.

Is there a way to track how many messages I've used?

Currently, there is no built-in tracker in ChatGPT to see your remaining message quota. You'll need to manually estimate based on usage or wait for the system to notify you when limits are hit.

Do API users face the same daily message caps?

No. API usage for o3 and o4-mini is governed by rate limits (requests per minute and tokens per minute), not fixed daily message limits.

What is the limit of o3 in ChatGPT?

The o3 model in ChatGPT is limited to 50 messages per week for Plus, Team, and Enterprise users.Currently, free users cannot access the o3 model in ChatGPT.

What is the limit of ChatGPT o4-mini?

The o4-mini model in ChatGPT is limited to 150 messages per day for Plus, Team, and Enterprise users, and is not available to free users.

What is the limit of ChatGPT o4-mini-high?

The o4-mini-high model in ChatGPT is limited to 50 messages per day for Plus, Team, and Enterprise users, and is not available to free users.