Claude Sonnet 4 vs Kimi K2 Thinking
Anthropic Claude Sonnet 4 | Moonshot AI Kimi K2 Thinking | |
|---|---|---|
| Overview | ||
| Company | Anthropic | Moonshot AI |
| Release date | May 22 2025 | Nov 6 2025 |
| Access | Proprietary | Open Weight |
| Specifications | ||
Parameters | — | 1T |
Context window | — | 256k |
| Benchmarks | ||
Nonsense detection BullshitBench v2Given a confidently-worded but nonsensical prompt, does the AI spot that it makes no sense and push back — instead of playing along and inventing an answer? The score is how often it clearly called out the nonsense. Higher is better. | 30% | — |
Coding SWE-Bench VerifiedReal coding tasks pulled from open-source projects — the AI has to find and fix actual bugs. A human-checked version of the original SWE-Bench. Higher is better. | 72.7%Best | 71.3% |
Science GPQA DiamondGraduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better. | 75.4% | — |
| Timeline | ||
| Release gap | Claude Sonnet 4 shipped 168 days before Kimi K2 Thinking | |
Which is better: Claude Sonnet 4 or Kimi K2 Thinking?
Claude Sonnet 4 leads Kimi K2 Thinking on 1 of the 1 benchmark they both report (SWE-Bench Verified). Claude Sonnet 4 shipped 168 days before Kimi K2 Thinking, so benchmark comparisons should account for the intervening progress.
Claude Sonnet 4 is proprietary, while Kimi K2 Thinking is open weight.
On SWE-Bench Verified, Claude Sonnet 4 leads at 72.7% vs Kimi K2 Thinking at 71.3%.
Frequently asked questions
Claude Sonnet 4 was released by Anthropic on May 22 2025.
Kimi K2 Thinking was released by Moonshot AI on Nov 6 2025.
Claude Sonnet 4 leads on SWE-Bench Verified — Claude Sonnet 4 72.7% vs Kimi K2 Thinking 71.3%.
Claude Sonnet 4 is a proprietary model released by Anthropic. Kimi K2 Thinking is an open weight model released by Moonshot AI.
Other comparisons
Claude Sonnet 4 vs GPT-5.6 SolKimi K2 Thinking vs GPT-5.6 SolClaude Sonnet 4 vs Gemini OmniKimi K2 Thinking vs Gemini OmniClaude Sonnet 4 vs Muse Spark 1.1Kimi K2 Thinking vs Muse Spark 1.1Claude Sonnet 4 vs Grok 4.5Kimi K2 Thinking vs Grok 4.5Claude Sonnet 4 vs DeepSeek-V4-ProKimi K2 Thinking vs DeepSeek-V4-ProClaude Sonnet 4 vs Mistral Medium 3.5Kimi K2 Thinking vs Mistral Medium 3.5