Model Comparison

Claude Sonnet 4.5 vs Kimi K2 Instruct

Claude Sonnet 4.5 significantly outperforms across most benchmarks. Kimi K2 Instruct is 12.0x cheaper per token.

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Performance Benchmarks

Comparative analysis across standard metrics

4 benchmarks

Claude Sonnet 4.5 outperforms in 4 benchmarks (AIME 2025, GPQA, SWE-bench Verified (Agentic Coding), Terminal-Bench), while Kimi K2 Instruct is better at 0 benchmarks.

Claude Sonnet 4.5 significantly outperforms across most benchmarks.

Tue May 26 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

Kimi K2 Instruct costs less

For input processing, Claude Sonnet 4.5 ($3.00/1M tokens) is 6.0x more expensive than Kimi K2 Instruct ($0.50/1M tokens).

For output processing, Claude Sonnet 4.5 ($15.00/1M tokens) is 30.0x more expensive than Kimi K2 Instruct ($0.50/1M tokens).

In conclusion, Claude Sonnet 4.5 is more expensive than Kimi K2 Instruct.*

* Using a 3:1 ratio of input to output tokens

Lowest available price from all providers
Tue May 26 2026 • llm-stats.com
Anthropic
Claude Sonnet 4.5
Input tokens$3.00
Output tokens$15.00
Best providerAnthropic
Moonshot AI
Kimi K2 Instruct
Input tokens$0.50
Output tokens$0.50
Best providerFireworks
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

Both models have the same input context window of 200,000 tokens. Kimi K2 Instruct can generate longer responses up to 200,000 tokens, while Claude Sonnet 4.5 is limited to 64,000 tokens.

Anthropic
Claude Sonnet 4.5
Input200,000 tokens
Output64,000 tokens
Moonshot AI
Kimi K2 Instruct
Input200,000 tokens
Output200,000 tokens
Tue May 26 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Claude Sonnet 4.5 supports multimodal inputs, whereas Kimi K2 Instruct does not.

Claude Sonnet 4.5 can handle both text and other forms of data like images, making it suitable for multimodal applications.

Claude Sonnet 4.5

Text
Images
Audio
Video

Kimi K2 Instruct

Text
Images
Audio
Video

License

Usage and distribution terms

Claude Sonnet 4.5 is licensed under a proprietary license, while Kimi K2 Instruct uses MIT.

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

Claude Sonnet 4.5

Proprietary

Closed source

Kimi K2 Instruct

MIT

Open weights

Release Timeline

When each model was launched

Claude Sonnet 4.5 was released on 2025-09-29, while Kimi K2 Instruct was released on 2025-07-11.

Claude Sonnet 4.5 is 3 months newer than Kimi K2 Instruct.

Claude Sonnet 4.5

Sep 29, 2025

7 months ago

2mo newer
Kimi K2 Instruct

Jul 11, 2025

10 months ago

Knowledge Cutoff

When training data ends

Claude Sonnet 4.5 has a documented knowledge cutoff of 2025-01-31, while Kimi K2 Instruct's cutoff date is not specified.

We can confirm Claude Sonnet 4.5's training data extends to 2025-01-31, but cannot make a direct comparison without Kimi K2 Instruct's cutoff date.

Claude Sonnet 4.5

Jan 2025

Kimi K2 Instruct

—

Provider Availability

Claude Sonnet 4.5 is available from Anthropic. Kimi K2 Instruct is available from Fireworks, Novita.

Claude Sonnet 4.5

anthropic logo
Anthropic
Input Price:Input: $3.00/1MOutput Price:Output: $15.00/1M

Kimi K2 Instruct

fireworks logo
Fireworks
Input Price:Input: $0.50/1MOutput Price:Output: $0.50/1M
novita logo
Novita
Input Price:Input: $0.57/1MOutput Price:Output: $2.30/1M
* Prices shown are per million tokens

Outputs Comparison

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Key Takeaways

Anthropic
Supports multimodal inputs
Higher AIME 2025 score (87.0% vs 49.5%)
Higher GPQA score (83.4% vs 75.1%)
Higher SWE-bench Verified (Agentic Coding) score (77.2% vs 65.8%)
Higher Terminal-Bench score (50.0% vs 30.0%)
Moonshot AI
Less expensive input tokens
Less expensive output tokens
Has open weights

Detailed Comparison

AI Model Comparison Table
Feature
Anthropic
Claude Sonnet 4.5
Moonshot AI
Kimi K2 Instruct

FAQ

Common questions about Claude Sonnet 4.5 vs Kimi K2 Instruct.

Which is better, Claude Sonnet 4.5 or Kimi K2 Instruct?

Claude Sonnet 4.5 significantly outperforms across most benchmarks. Claude Sonnet 4.5 is made by Anthropic and Kimi K2 Instruct 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 4.5 compare to Kimi K2 Instruct in benchmarks?

Claude Sonnet 4.5 scores MMMLU: 89.1%, AIME 2025: 87.0%, TAU-bench Retail: 86.2%, GPQA: 83.4%, MMMUval: 77.8%. Kimi K2 Instruct scores MATH-500: 97.4%, GSM8k: 97.3%, CBNSL: 95.6%, HumanEval: 93.3%, MMLU-Redux: 92.7%.

Is Claude Sonnet 4.5 cheaper than Kimi K2 Instruct?

Kimi K2 Instruct is 6.0x cheaper for input tokens. Claude Sonnet 4.5 costs $3.00/M input and $15.00/M output via anthropic. Kimi K2 Instruct costs $0.50/M input and $0.50/M output via fireworks.

What are the context window sizes for Claude Sonnet 4.5 and Kimi K2 Instruct?

Claude Sonnet 4.5 supports 200K tokens and Kimi K2 Instruct supports 200K 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 4.5 and Kimi K2 Instruct?

Key differences include input pricing ($3.00 vs $0.50/M), multimodal support (yes vs no), licensing (Proprietary vs MIT). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Sonnet 4.5 and Kimi K2 Instruct?

Claude Sonnet 4.5 is developed by Anthropic and Kimi K2 Instruct is developed by Moonshot AI.