100% free & open source · No account required

Jan — Local AI Chat for Windows

An open-source ChatGPT alternative that runs entirely on your PC. Download models once, then chat completely offline.

Download for Windows

Direct link from jan.ai · Also available on the Microsoft Store · Windows 10 or later

License

Apache 2.0

Cost

Free

Install size

< 200 MB

Engine

llama.cpp

What you get

🔌

Works fully offline

After downloading a model, chat with zero internet connection — nothing leaves your PC.

📦

Built-in model library

Browse and download Llama, Gemma, Qwen, and other open models from inside the app.

🔗

Optional cloud models

Bring your own API key to also chat with GPT, Claude, or Mistral from the same interface.

🖥️

Local API server

An OpenAI-compatible endpoint at localhost:1337 for your own scripts and tools.

How to install it

  1. Click the download button above

    This is a direct link from jan.ai's own servers — the same file the site's "Download" button gives you.

  2. Run jan.exe

    Standard Windows installer — no license key, no sign-up required to install.

  3. Pick a model matched to your RAM

    The built-in model browser flags which models fit comfortably on your hardware.

  4. Start chatting

    Once the model finishes downloading, everything runs locally — no account needed.

How much RAM you actually need

8 GB RAMComfortable with 3B-parameter models
16 GB RAMComfortable with 7B-parameter models
32 GB RAMComfortable with 13B+ parameter models
Disk spaceAt least 5 GB free for models, more for larger ones
Good to know: This is an independent overview, not affiliated with Jan or Menlo Research. The button above links straight to jan.ai's own download server — this page never hosts or serves the installer itself, which is the safest way to get it. A GPU is optional; Jan runs on CPU-only machines too, just slower.