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Claude Sonnet 4 vs Kimi K2-Instruct-0905

Claude Sonnet 4 significantly outperforms across most benchmarks.

Anthropic · Moonshot AI · Updated for 2026

Which is better?

Claude Sonnet 4 outperforms in 4 benchmarks (AIME 2025, GPQA, SWE-Bench Verified, Terminal-Bench), while Kimi K2-Instruct-0905 is better at 0 benchmarks. Claude Sonnet 4 significantly outperforms across most benchmarks.

Based on current benchmark, pricing, and model metadata for 2026.

Choose Claude Sonnet 4

  • you want the strongest raw capability — it leads on 4 of 4 shared benchmarks

Choose Kimi K2-Instruct-0905

  • you want the most recent training data — it shipped Sep 2025
  • you need open weights you can self-host or fine-tune

At a glance

The differences that matter most.

Claude Sonnet 4
Anthropic
Kimi K2-Instruct-0905
Moonshot AI
Benchmark wins
4 of 4
0 of 4
Input price
$3.00 / M
— / M
Output price
$15.00 / M
— / M
Context window
200,000
—
Released
May 2025
Sep 2025
License
Proprietary
MIT

Performance Benchmarks

Comparative analysis across standard metrics

4 benchmarks

Claude Sonnet 4 outperforms in 4 benchmarks (AIME 2025, GPQA, SWE-Bench Verified, Terminal-Bench), while Kimi K2-Instruct-0905 is better at 0 benchmarks.

Claude Sonnet 4 significantly outperforms across most benchmarks.

Mon Aug 24 2026 • llm-stats.com

Arena Performance

Playground indexes and blind preference scores

Context Window

Maximum input and output token capacity

Only Claude Sonnet 4 specifies input context (200,000 tokens). Only Claude Sonnet 4 specifies output context (64,000 tokens).

Anthropic
Claude Sonnet 4
Input200,000 tokens
Output64,000 tokens
Moonshot AI
Kimi K2-Instruct-0905
Input- tokens
Output- tokens
Mon Aug 24 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Claude Sonnet 4 supports multimodal inputs, whereas Kimi K2-Instruct-0905 does not.

Claude Sonnet 4 can handle both text and other forms of data like images, making it suitable for multimodal applications.

Claude Sonnet 4

Text
Images
Audio
Video

Kimi K2-Instruct-0905

Text
Images
Audio
Video

License

Usage and distribution terms

Claude Sonnet 4 is licensed under a proprietary license, while Kimi K2-Instruct-0905 uses MIT.

License differences may affect how you can use these models in commercial or open-source projects.

Claude Sonnet 4

Proprietary

Closed source

Kimi K2-Instruct-0905

MIT

Open weights

Release Timeline

When each model was launched

Claude Sonnet 4 was released on 2025-05-22, while Kimi K2-Instruct-0905 was released on 2025-09-05.

Kimi K2-Instruct-0905 is 4 months newer than Claude Sonnet 4.

Claude Sonnet 4

May 22, 2025

1.3 years ago

Kimi K2-Instruct-0905

Sep 5, 2025

11 months ago

3mo newer

Knowledge Cutoff

When training data ends

Neither model specifies a knowledge cutoff date.

Unable to compare the recency of their training data.

No cutoff dates available

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Judge for yourself.

Run your own prompts against Claude Sonnet 4 and Kimi K2-Instruct-0905 side-by-side, then vote on the output you prefer.

Claude Sonnet 4
✓ Preferred
Kimi K2-Instruct-0905
Open in Playground

FAQ

Common questions about Claude Sonnet 4 vs Kimi K2-Instruct-0905.

Which is better, Claude Sonnet 4 or Kimi K2-Instruct-0905?

Claude Sonnet 4 significantly outperforms across most benchmarks. Claude Sonnet 4 is made by Anthropic and Kimi K2-Instruct-0905 is made by Moonshot AI. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does Claude Sonnet 4 compare to Kimi K2-Instruct-0905 in benchmarks?

Claude Sonnet 4 scores MMMLU: 86.5%, TAU-bench Retail: 80.5%, GPQA: 75.4%, MMMU: 74.4%, SWE-Bench Verified: 72.7%. Kimi K2-Instruct-0905 scores MATH-500: 97.4%, MMLU-Redux: 92.7%, IFEval: 89.8%, AutoLogi: 89.5%, MMLU: 89.5%.

What are the context window sizes for Claude Sonnet 4 and Kimi K2-Instruct-0905?

Claude Sonnet 4 supports 200K tokens and Kimi K2-Instruct-0905 supports an unknown number of tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Claude Sonnet 4 and Kimi K2-Instruct-0905?

Key differences include multimodal support (yes vs no), licensing (Proprietary vs MIT). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Sonnet 4 and Kimi K2-Instruct-0905?

Claude Sonnet 4 is developed by Anthropic and Kimi K2-Instruct-0905 is developed by Moonshot AI.

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