FrontierFebruary 27, 2025via OpenAI Blog

Introducing GPT-4.5

Why it matters

OpenAI's largest model yet signals a continued race on pre-training and post-training optimization. For founders and investors, this sets a new baseline for what 'state-of-the-art' means in Feb 2025—and what capabilities competitors need to match.

Key signals

  • GPT-4.5 announced as research preview
  • Positioned as 'largest and best model for chat yet'
  • Focus on scaling pre-training and post-training
  • Released Feb 27, 2025
  • OpenAI official announcement channel

The hook

OpenAI just shipped GPT-4.5. Here's what changed in scaling.

We’re releasing a research preview of GPT‑4.5—our largest and best model for chat yet. GPT‑4.5 is a step forward in scaling up pre-training and post-training.

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