Claude 3.5 SonnetvsKimi K2.6
Claude 3.5 Sonnet | Kimi K2.6 | |
|---|---|---|
| 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 | ||
Input priceWhat you pay for everything you send the model — your question, plus any documents or earlier conversation you include with it. | — | $0.95 |
Output priceWhat you pay for the text the model writes back. It is normally the dearer half: producing an answer costs more than reading one. | — | $4.00 |
Cached input priceA reduced rate for text you send over and over. If every request starts with the same instructions or the same document, the provider keeps a copy ready and charges less to read it again. | — | $0.16 |
| Benchmarks | ||
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% | 65% |
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% | 80.2% |
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% | 90.5% |
| BenchmarksPublished by one model only | ||
CursorBench v3.1Agentic coding — Cursor's own test of harder, real-world coding tasks inside a code editor. Higher is better. | — | 47.6% |
Next.js EvalsNext.js coding — Vercel's open eval of how well AI coding agents build and migrate real Next.js apps — measured as the share of tasks the agent completes successfully. Higher is better. | — | 67% |
LiveCodeBenchCompetitive coding — Coding problems published so recently the AI can't have seen them in training — a contamination-free test of raw programming skill. Higher is better. | — | 89.6% |
Arena Elo (Text)Community preference — Real people chat with two anonymous AIs side by side and vote for the answer they prefer. Votes become a chess-style Elo rating on arena.ai — it measures which AI people actually like, not test scores. Higher is better. | — | 1461 |
Arena Elo (Code)Community preference (code) — Like the text arena, but people vote on which AI writes better code. The votes become a chess-style Elo rating on arena.ai. Higher is better. | — | 1513 |
| Overview | ||
| Company | Anthropic | Moonshot AI |
| Release date | Jun 20 2024 | Apr 21 2026 |
| Access | Proprietary | Open Weight |
Frequently asked questions
Kimi K2.6 leads Claude 3.5 Sonnet on 3 of the 3 benchmarks they both report (BullshitBench v2, SWE-Bench Verified, GPQA Diamond). Only Kimi K2.6 has a verified first-party API price: $0.95 per million input tokens and $4.00 per million output tokens. No pay-as-you-go API rate is tracked for Claude 3.5 Sonnet. Claude 3.5 Sonnet shipped 670 days before Kimi K2.6, so benchmark comparisons should account for the intervening progress.
Claude 3.5 Sonnet is proprietary, while Kimi K2.6 is open weight.
On BullshitBench v2, Kimi K2.6 leads at 65% vs Claude 3.5 Sonnet at 45%. On SWE-Bench Verified, Kimi K2.6 leads at 80.2% vs Claude 3.5 Sonnet at 33.4%. On GPQA Diamond, Kimi K2.6 leads at 90.5% vs Claude 3.5 Sonnet at 59.4%.
Claude 3.5 Sonnet was released by Anthropic on Jun 20 2024.
Kimi K2.6 was released by Moonshot AI on Apr 21 2026.
Kimi K2.6 leads on SWE-Bench Verified — Claude 3.5 Sonnet 33.4% vs Kimi K2.6 80.2%.
Kimi K2.6 leads on GPQA Diamond — Claude 3.5 Sonnet 59.4% vs Kimi K2.6 90.5%.
Only Kimi K2.6 has a verified first-party API price: $0.95 per million input tokens and $4.00 per million output tokens. No pay-as-you-go API rate is tracked for Claude 3.5 Sonnet. Rates are pay-as-you-go API prices verified on August 18, 2026.
Claude 3.5 Sonnet is a proprietary model released by Anthropic. Kimi K2.6 is an open weight model released by Moonshot AI.