Claude 3.5 SonnetvsKimi K2 Thinking
Claude 3.5 Sonnet | Kimi K2 Thinking | |
|---|---|---|
| Specifications | ||
ParametersA rough measure of how big the model is. More parameters usually means more capable and more expensive to run, though it is a poor guide on its own — a smaller, newer model often beats a larger, older one. | — | 1T |
Context windowHow much text the model can hold in mind at once — your question, any documents you attach, the conversation so far, and its own reply. Go past it and the earliest part falls out of view. | — | 256k |
| API pricingUSD per 1M tokens · lower wins | ||
Cheapest inputLowest input rate across third-party providers, excluding the lab itself. The cheapest endpoint may run a quantised build or a shorter context — see "Available from" on the model page. | — | $0.60Google |
Cheapest outputLowest output rate across third-party providers, excluding the lab itself. May come from a different provider than the cheapest input. | — | $2.50Google |
| Benchmarks | ||
SWE-Bench VerifiedCoding — Real 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% |
| BenchmarksPublished by one model only | ||
BullshitBench v2Nonsense detection — Given 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% | — |
GPQA DiamondScience — Graduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better. | 59.4% | — |
| Overview | ||
| Company | Anthropic | Moonshot AI |
| Release date | Jun 20 2024 | Nov 6 2025 |
| Access | Proprietary | Open Weight |
Other comparisons
Claude 3.5 SonnetvsGPT-5.6 SolKimi K2 ThinkingvsGPT-5.6 SolClaude 3.5 SonnetvsGemini 3.7 FlashKimi K2 ThinkingvsGemini 3.7 FlashClaude 3.5 SonnetvsMuse GlimmerKimi K2 ThinkingvsMuse GlimmerClaude 3.5 SonnetvsGrok 4.6Kimi K2 ThinkingvsGrok 4.6Claude 3.5 SonnetvsDeepSeek-V4-Pro-0813Kimi K2 ThinkingvsDeepSeek-V4-Pro-0813Claude 3.5 SonnetvsMistral Medium 3.5Kimi K2 ThinkingvsMistral Medium 3.5
Frequently asked questions
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%.
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.