1 vs 1 benchmarks won
Anthropic Claude Sonnet 4 | OpenAI GPT-5.5 | |
|---|---|---|
| Overview | ||
| Company | Anthropic | OpenAI |
| Release date | May 22 2025 | Apr 23 2026 |
| Model type | — | — |
| Open source | No | No |
| Specifications | ||
Parameters | — | — |
Context window | — | — |
| Benchmarks | ||
Science reasoning GPQA Diamond | 75.4% | 93.6% |
Software engineering SWE-Bench Verified | 72.7% | — |
Multimodal understanding MMMU | — | — |
| Timeline | ||
| Release gap | Claude Sonnet 4 shipped 336 days before GPT-5.5 | |
Claude Sonnet 4 and GPT-5.5 are evenly matched across the benchmarks they both publish. Claude Sonnet 4 shipped 336 days before GPT-5.5, 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.
On GPQA Diamond, GPT-5.5 scores 93.6%, 18.2 points above Claude Sonnet 4 at 75.4%.