3 vs 0 benchmarks won
Anthropic Claude Sonnet 4.5 | Moonshot AI Kimi K2 Thinking | |
|---|---|---|
| Overview | ||
| Company | Anthropic | Moonshot AI |
| Release date | Sep 29 2025 | Nov 6 2025 |
| Model type | — | — |
| Open source | No | Yes |
| Specifications | ||
Parameters | — | 1T |
Context window | — | 256k |
| Benchmarks | ||
Science reasoning GPQA Diamond | 83.4% | — |
Software engineering SWE-Bench Verified | 77.2% | 71.3% |
Multimodal understanding MMMU | 68% | — |
| Timeline | ||
| Release gap | Claude Sonnet 4.5 shipped 38 days before Kimi K2 Thinking | |
Claude Sonnet 4.5 leads Kimi K2 Thinking on 3 of the tracked benchmarks (GPQA Diamond, SWE-Bench Verified, MMMU). Claude Sonnet 4.5 shipped 38 days before Kimi K2 Thinking, so benchmark comparisons should account for the intervening progress.
Kimi K2 Thinking is an open-source / open-weight model; Claude Sonnet 4.5 is proprietary.
On SWE-Bench Verified, Claude Sonnet 4.5 scores 77.2%, 5.9 points above Kimi K2 Thinking at 71.3%.