Anthropic Claude 2.1 vs OpenAI o3-pro — side-by-side specs.
Anthropic Claude 2.1 | OpenAI o3-pro | |
|---|---|---|
| Overview | ||
| Company | Anthropic | OpenAI |
| Release date | Nov 21 2023 | Jun 10 2025 |
| Model type | — | — |
| Open source | No | No |
| Specifications | ||
Parameters | — | — |
Context window | — | — |
| Benchmarks | ||
| Timeline | ||
| Release gap | Claude 2.1 shipped 567 days before o3-pro | |
Claude 2.1 and o3-pro don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. Claude 2.1 shipped 567 days before o3-pro, so benchmark comparisons should account for the intervening progress.
Published specifications for these two models are limited — see each model page for the latest details.
Direct benchmark comparisons are unavailable — Claude 2.1 and o3-pro don't publish scores on any of the same benchmarks.