Run ChatGPT Offline On Your Mac With LM Studio

Why Run a Large Language Model Locally?

Have you ever wanted to use a powerful AI like ChatGPT without an internet connection? Running a Large Language Model (LLM) like gpt-oss, ChatGPT's open model, directly on your Mac makes this possible. This approach offers several fantastic benefits, including complete offline access and enhanced privacy. Whether you're an AI enthusiast, a developer, or just curious about experimenting with these tools, setting up a local LLM is a compelling project. It's also a great option if you prefer the GPT-4 model and want a reliable way to access its capabilities.

This guide provides a simple, step-by-step method to get gpt-oss running locally on your Mac. While the focus is on macOS, the same principles apply to Windows and Linux systems using the same tools.

Choosing the Right Model for Your Mac

Before we start, it's important to know there are two versions of gpt-oss available. We'll be using the gpt-oss-20b model, which is a great starting point. It requires about 16GB of storage, making it manageable for most modern Macs. The larger gpt-oss-120b model needs over 120GB of space and is better suited for high-performance machines. For our purposes, the 20b model runs smoothly on M-series Apple Silicon Macs and is more than powerful enough for most tasks. Remember, you'll need an internet connection for the initial download, but after that, it's all offline.

Your Step-by-Step Guide to a Local GPT Setup

Getting gpt-oss running on your Mac is surprisingly easy with the free LM Studio app. Here’s exactly what you need to do:

1. Download LM Studio: Head over to the official website and download the free LM Studio application.

   

2. Launch and Configure: Open LM Studio and choose the "Power User" option when prompted.

   

3. Download the Model: On the next screen, ensure gpt-oss is selected and click the "Download gpt-oss" button. This will begin downloading the 16GB model file.

   

4. Start a Chat: Once the download is complete, click "Start a New Chat".

   

5. Select the Model: In the new chat window, click the model selection dropdown at the top of the screen.

   

6. Load gpt-oss: Choose "openai/gpt-oss" from the list. The application will now load the model into memory.

   

7. Start Interacting: As soon as the model is loaded, you're ready to go! You can now chat with your local gpt-oss instance just like you would with any other chatbot.

   

What Can You Do With Your Offline AI?

Enjoy your private, local GPT experience! This offline model is incredibly versatile. You can use it to answer questions, solve math problems, draft letters and reports, analyze data, write code, and much more—all without an internet connection.

Because it runs offline, gpt-oss won't have access to real-time information from the web. However, it's built on a massive dataset, making it a powerful and knowledgeable tool right out of the box.

Privacy, Security, and Other Models

The ability to run models offline is a game-changer for privacy-focused users. You can experiment and interact with an LLM without your data being used for training or shared online. For maximum security, you could even set up gpt-oss within a virtual machine that has its network access completely disabled.

AI tools are here to stay, and having a local instance gives you more control. If you're interested in exploring further, LM Studio also supports other models, including Llama and DeepSeek.

For more great content, feel free to explore other AI articles or dive into our ChatGPT-specific posts.