Phi (language model)
Microsoft free and open-source large language model
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Phi is a series of large language models developed by Microsoft that are open-weights and can run locally on one's device.
The initial version, Phi-1, released in June 2023. Phi-3 was released in April 2024. Phi-4-reasoning-vision-15B was released in March 2026.
The New York Times considered Phi-3-mini to be Microsoft's push into smaller large language models. Phi-3-mini has 3.8 billion parameters. Phi-3-mini has been compared to GPT-3.5 in terms of capability.
History
On June 21, 2023, Microsoft released Phi-1 with 1.3 billion parameters.[2]
In April 2024, Microsoft released Phi-3-mini as an open-weights model with 3.8 billion parameters. Phi-3-mini is capable of running on a phone.[3]
In March 2026, Phi-4-reasoning-vision-15B was released, with the capability of deciding when to reason.[4]
Models
Phi-3-mini
Phi-3-mini was released in April 2024.[5] It has 3.8 billion parameters and it was released into Azure. It is also capable of running on a phone.[3]
The New York Times considered Phi-3-mini to be Microsoft's push into smaller language models.[5] WIRED and Ars Technica considered Phi-3-mini to be of similar quality to GPT-3.5.[6]
Phi-4-reasoning-vision-15B
Phi-4-reasoning-vision-15B was released in March 2026. It is capable of deciding when to provide a reasoning process before answering the user prompt, and when to skip reasoning. It has 15 billion parameters, and is a vision-language model.[4]