Claude Sonnet 4.5 vs Kimi K3
Anthropic Claude Sonnet 4.5 | Moonshot AI Kimi K3 | |
|---|---|---|
| Overview | ||
| Company | Anthropic | Moonshot AI |
| Release date | Sep 29 2025 | Jul 16 2026 |
| Access | Proprietary | Open Weight |
| Specifications | ||
Parameters | — | 2.8T |
Context window | — | 1M |
| 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. | 79% | — |
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. | 77.2% | — |
Agentic coding DeepSWE 1.0Artificial Analysis' independent test of deep, agentic software-engineering work — the AI has to plan and carry out substantial coding tasks end to end. Higher is better. | — | 67.5% |
Next.js coding Next.js EvalsVercel'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. | 50% | — |
Agentic terminal coding Terminal-Bench 2.1Can the AI work in a command-line terminal — running commands and finishing technical setup tasks the way a developer would? Higher is better. | — | 88.3% |
Multi-step tool use MCP AtlasCan the AI chain together many tools and steps to complete one bigger task, rather than doing just a single thing? Higher is better. | — | 84.2% |
Professional tool use JobBenchTests the AI on professional workplace tasks that require using real work tools — the kind of multi-step jobs an office worker handles. Higher is better. | — | 52.9% |
Personal tool use Toolathlon-VerifiedTests how well the AI uses everyday personal tools and apps to get things done — a human-checked version of Toolathlon. Higher is better. | — | 73.2% |
Web browsing BrowseCompCan the AI browse the web and track down hard-to-find answers? Higher is better. | — | 91.2% |
Multidisciplinary reasoning Humanity's Last Exam · no toolsHumanity's Last Exam — extremely hard expert questions across many subjects, written so you can't just look up the answer. “No tools” means the AI answers on its own. Higher is better. | — | 43.5% |
Multidisciplinary reasoning Humanity's Last Exam · with toolsHumanity's Last Exam — extremely hard expert questions across many subjects. “With tools” means the AI is allowed to search the web or run code while answering. Higher is better. | — | 56% |
Science GPQA DiamondGraduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better. | 83.4% | 93.5%Best |
Knowledge work GDPval-AA v2economically valuable knowledge work (v2, re-based Elo) | — | 1668 |
Chart reasoning CharXiv ReasoningCan the AI read and reason about complex charts and figures, not just text? Higher is better. | — | 84.8% |
Multimodal reasoning MMMU-ProA tougher version of MMMU — college-level questions that mix images, diagrams, and text together. Higher is better. | — | 81.6% |
Multimodal MMMUTests the AI on understanding images and text together across many college subjects. Higher is better. | 68% | — |
| Timeline | ||
| Release gap | Claude Sonnet 4.5 shipped 290 days before Kimi K3 | |
Which is better: Claude Sonnet 4.5 or Kimi K3?
Kimi K3 leads Claude Sonnet 4.5 on 1 of the 1 benchmark they both report (GPQA Diamond). Claude Sonnet 4.5 shipped 290 days before Kimi K3, so benchmark comparisons should account for the intervening progress.
Claude Sonnet 4.5 is proprietary, while Kimi K3 is open weight.
On GPQA Diamond, Kimi K3 leads at 93.5% vs Claude Sonnet 4.5 at 83.4%.
Frequently asked questions
Claude Sonnet 4.5 was released by Anthropic on Sep 29 2025.
Kimi K3 was released by Moonshot AI on Jul 16 2026.
Kimi K3 leads on GPQA Diamond — Claude Sonnet 4.5 83.4% vs Kimi K3 93.5%.
Claude Sonnet 4.5 is a proprietary model released by Anthropic. Kimi K3 is an open weight model released by Moonshot AI.
Other comparisons
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