Model Comparison
Claude Sonnet 4 vs Kimi K2 0905Which is better in 2026?
Kimi K2 0905 significantly outperforms across most benchmarks. Kimi K2 0905 is 5.6x cheaper per token.
Verdict: Claude Sonnet 4 vs Kimi K2 0905 — which is better?
Claude Sonnet 4 (by Anthropic) and Kimi K2 0905 (by Moonshot AI) are two of the AI models people compare most. Here is how they stack up on benchmarks, price and capabilities, and which one to pick in 2026.
Claude Sonnet 4 outperforms in 0 benchmarks, while Kimi K2 0905 is better at 1 benchmark (GPQA). Kimi K2 0905 significantly outperforms across most benchmarks.
On price, Kimi K2 0905 is roughly 5.6x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
Kimi K2 0905 also accepts a larger context window (262,144 input tokens), making it the stronger choice for long documents and large codebases.
Choose Claude Sonnet 4 if…
- you want predictable pricing at $3.00/M input and $15.00/M output
Choose Kimi K2 0905 if…
- you want the strongest raw capability — it leads on 1 of 1 shared benchmarks
- cost matters — it's about 5.6x cheaper per token
- you process long inputs — it offers a 262,144 token context window
- you want the most recent training data — it shipped Sep 2025
Performance Benchmarks
Comparative analysis across standard metrics
Claude Sonnet 4 outperforms in 0 benchmarks, while Kimi K2 0905 is better at 1 benchmark (GPQA).
Kimi K2 0905 significantly outperforms across most benchmarks.
Arena Performance
Human preference votes
Pricing Analysis
Price comparison per million tokens
For input processing, Claude Sonnet 4 ($3.00/1M tokens) is 5.0x more expensive than Kimi K2 0905 ($0.60/1M tokens).
For output processing, Claude Sonnet 4 ($15.00/1M tokens) is 6.0x more expensive than Kimi K2 0905 ($2.50/1M tokens).
In conclusion, Claude Sonnet 4 is more expensive than Kimi K2 0905.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
Kimi K2 0905 accepts 262,144 input tokens compared to Claude Sonnet 4's 200,000 tokens. Kimi K2 0905 can generate longer responses up to 262,144 tokens, while Claude Sonnet 4 is limited to 64,000 tokens.
Input Capabilities
Supported data types and modalities
Claude Sonnet 4 supports multimodal inputs, whereas Kimi K2 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
Kimi K2 0905
License
Usage and distribution terms
Both models are licensed under proprietary licenses.
Both models have usage restrictions defined by their respective organizations.
Proprietary
Closed source
Proprietary
Closed source
Release Timeline
When each model was launched
Claude Sonnet 4 was released on 2025-05-22, while Kimi K2 0905 was released on 2025-09-05.
Kimi K2 0905 is 4 months newer than Claude Sonnet 4.
May 22, 2025
1.2 years ago
Sep 5, 2025
10 months ago
3mo newerKnowledge Cutoff
When training data ends
Neither model specifies a knowledge cutoff date.
Unable to compare the recency of their training data.
Provider Availability
Claude Sonnet 4 is available from Anthropic, Bedrock, Google. Kimi K2 0905 is available from Novita.
Claude Sonnet 4
Kimi K2 0905
Outputs Comparison
Key Takeaways
Claude Sonnet 4
View detailsAnthropic
Kimi K2 0905
View detailsMoonshot AI
Claude Sonnet 4Kimi K2 0905Detailed Comparison
Interactive Arena
Judge for yourself.
Run your own prompts against Claude Sonnet 4 and Kimi K2 0905 side-by-side, then vote on the output you prefer.
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FAQ
Common questions about Claude Sonnet 4 vs Kimi K2 0905.