Claude 3.5 Sonnet vs Kimi K2 Thinking
Anthropic Claude 3.5 Sonnet | Moonshot AI Kimi K2 Thinking | |
|---|---|---|
| Overview | ||
| Company | Anthropic | Moonshot AI |
| Release date | Jun 20 2024 | 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. | 45% | — |
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. | 33.4% | 71.3%Best |
Science GPQA DiamondGraduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better. | 59.4% | — |
| Timeline | ||
| Release gap | Claude 3.5 Sonnet shipped 504 days before Kimi K2 Thinking | |
Which is better: Claude 3.5 Sonnet or Kimi K2 Thinking?
Kimi K2 Thinking leads Claude 3.5 Sonnet on 1 of the 1 benchmark they both report (SWE-Bench Verified). Claude 3.5 Sonnet shipped 504 days before Kimi K2 Thinking, so benchmark comparisons should account for the intervening progress.
Claude 3.5 Sonnet is proprietary, while Kimi K2 Thinking is open weight.
On SWE-Bench Verified, Kimi K2 Thinking leads at 71.3% vs Claude 3.5 Sonnet at 33.4%.
Frequently asked questions
Claude 3.5 Sonnet was released by Anthropic on Jun 20 2024.
Kimi K2 Thinking was released by Moonshot AI on Nov 6 2025.
Kimi K2 Thinking leads on SWE-Bench Verified — Claude 3.5 Sonnet 33.4% vs Kimi K2 Thinking 71.3%.
Claude 3.5 Sonnet is a proprietary model released by Anthropic. Kimi K2 Thinking is an open weight model released by Moonshot AI.
Other comparisons
Claude 3.5 Sonnet vs GPT-5.6 SolKimi K2 Thinking vs GPT-5.6 SolClaude 3.5 Sonnet vs Gemini OmniKimi K2 Thinking vs Gemini OmniClaude 3.5 Sonnet vs Muse Spark 1.1Kimi K2 Thinking vs Muse Spark 1.1Claude 3.5 Sonnet vs Grok 4.5Kimi K2 Thinking vs Grok 4.5Claude 3.5 Sonnet vs DeepSeek-V4-ProKimi K2 Thinking vs DeepSeek-V4-ProClaude 3.5 Sonnet vs Mistral Medium 3.5Kimi K2 Thinking vs Mistral Medium 3.5