Compare models
Pick up to 4models. Specs render side-by-side. Share the URL — it's stateless.
 o3OpenAI | GPT-5.5 OpenAI |  Claude 4.5 HaikuAnthropic | |
|---|---|---|---|
| Vendor | OpenAI | OpenAI | Anthropic |
| Family | o-series | GPT | Claude |
| Release date | 2025-04-16 | 2026-04-23 | 2025-10-01 |
| Context window | 200,000 tokens | 400,000 tokens | 200,000 tokens |
| Parameters | — | — | — |
| Modality | text, vision | text, vision, audio | text, vision |
| License | proprietary | proprietary | proprietary |
| Source | proprietary | proprietary | proprietary |
| Description | Reasoning-focused model in the o-series. | OpenAI's smartest and most intuitive model — successor to GPT-5, with major coding, research, and document workflow gains. GPT-5.5 Pro variant also available for heavier reasoning. | Fast, cost-effective Claude model. |
| Links |
