When was GPT-4.5 released?

GPT-4.5 was released by OpenAI on Thursday, Feb 27 2025.

GPT-4.5 was built by OpenAI. Creators of ChatGPT and the GPT series of models. Pioneered large-scale language model research.

Is GPT-4.5 open source?

No. GPT-4.5 is a proprietary model. The weights are not published — it is available only through the provider's own API, apps, or partner platforms.

OpenAI's previous tracked release was o3-mini-high on Jan 31 2025, 27 days earlier. It was followed by o1-pro on Mar 19 2025.

Released Feb 27 2025

GPT-4.5 is an AI model released by OpenAI on Thursday, Feb 27 2025, 27 days after o3-mini-high.

GPT-4.5

: GPT-4.5 was released by OpenAI on Thursday, Feb 27 2025.
: GPT-4.5 was built by OpenAI. Creators of ChatGPT and the GPT series of models. Pioneered large-scale language model research.
: No. GPT-4.5 is a proprietary model. The weights are not published — it is available only through the provider's own API, apps, or partner platforms.
: OpenAI's previous tracked release was o3-mini-high on Jan 31 2025, 27 days earlier. It was followed by o1-pro on Mar 19 2025.