Claude 3.5 Sonnet (upgraded)vsKimi K2 Thinking
Claude 3.5 Sonnet (upgraded) | 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. | 49% | 71.3% |
| Overview | ||
| Company | Anthropic | Moonshot AI |
| Release date | Oct 22 2024 | Nov 6 2025 |
| Access | Proprietary | Open Weight |
Other comparisons
Frequently asked questions
Kimi K2 Thinking leads Claude 3.5 Sonnet (upgraded) on 1 of the 1 benchmark they both report (SWE-Bench Verified). Claude 3.5 Sonnet (upgraded) shipped 380 days before Kimi K2 Thinking, so benchmark comparisons should account for the intervening progress.
Claude 3.5 Sonnet (upgraded) 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 (upgraded) at 49%.
Claude 3.5 Sonnet (upgraded) was released by Anthropic on Oct 22 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 (upgraded) 49% vs Kimi K2 Thinking 71.3%.
Claude 3.5 Sonnet (upgraded) is a proprietary model released by Anthropic. Kimi K2 Thinking is an open weight model released by Moonshot AI.