GPT
OpenAIGPT (Generative Pre-trained Transformer) is OpenAI's flagship line of large language models. The series began with GPT-1 (2018) and has progressed through GPT-2 (2019), GPT-3 (2020), GPT-3.5 (2022, powering the original ChatGPT), GPT-4 (2023), and GPT-4o (2024). The o-series (o1, o3) extends GPT with chain-of-thought reasoning. GPT models are available via the OpenAI API, ChatGPT, and Microsoft Copilot.
GPT Family7
| Model | Tier | Released | Input $/MTok |
|---|---|---|---|
| GPT-4.1 | flagship | 2025-04-14 | $2 |
| GPT-4.1 mini | mini | 2025-04-14 | $0.4 |
| GPT-4.1 nano | nano | 2025-04-14 | $0.1 |
| GPT-4o mini | mini | 2024-07-18 | $0.15 |
| GPT-4o | flagship | 2024-05-13 | $2.5 |
| GPT-4 Turbo | flagship | 2023-11-06 | $10 |
| GPT-4 | flagship | 2023-03-14 | $30 |