Model Comparison

GPT-4o vs Kimi K2-Instruct-0905

Kimi K2-Instruct-0905 significantly outperforms across most benchmarks.

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Performance Benchmarks

Comparative analysis across standard metrics

13 benchmarks

GPT-4o outperforms in 2 benchmarks (Humanity's Last Exam, SimpleQA), while Kimi K2-Instruct-0905 is better at 11 benchmarks (Aider-Polyglot, AIME 2024, GPQA, IFEval, MMLU, MMLU-Pro, Multi-Challenge, SWE-Bench Verified, Tau2 Airline, Tau2 Retail, Tau2 Telecom).

Kimi K2-Instruct-0905 significantly outperforms across most benchmarks.

Mon May 25 2026 • llm-stats.com

Arena Performance

Human preference votes

Context Window

Maximum input and output token capacity

Only GPT-4o specifies input context (128,000 tokens). Only GPT-4o specifies output context (16,384 tokens).

OpenAI
GPT-4o
Input128,000 tokens
Output16,384 tokens
Moonshot AI
Kimi K2-Instruct-0905
Input- tokens
Output- tokens
Mon May 25 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

GPT-4o supports multimodal inputs, whereas Kimi K2-Instruct-0905 does not.

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

GPT-4o

Text
Images
Audio
Video

Kimi K2-Instruct-0905

Text
Images
Audio
Video

License

Usage and distribution terms

GPT-4o 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.

GPT-4o

Proprietary

Closed source

Kimi K2-Instruct-0905

MIT

Open weights

Release Timeline

When each model was launched

GPT-4o was released on 2024-08-06, while Kimi K2-Instruct-0905 was released on 2025-09-05.

Kimi K2-Instruct-0905 is 13 months newer than GPT-4o.

GPT-4o

Aug 6, 2024

1.8 years ago

Kimi K2-Instruct-0905

Sep 5, 2025

8 months ago

1.1yr 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

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Key Takeaways

OpenAI
Larger context window (128,000 tokens)
Supports multimodal inputs
Higher Humanity's Last Exam score (5.3% vs 4.7%)
Higher SimpleQA score (38.2% vs 31.0%)
Moonshot AI
Has open weights
Higher Aider-Polyglot score (60.0% vs 30.7%)
Higher AIME 2024 score (69.6% vs 13.1%)
Higher GPQA score (75.1% vs 70.1%)
Higher IFEval score (89.8% vs 81.0%)
Higher MMLU score (89.5% vs 85.7%)
Higher MMLU-Pro score (81.1% vs 74.7%)
Higher Multi-Challenge score (54.1% vs 40.3%)
Higher SWE-Bench Verified score (65.8% vs 33.2%)
Higher Tau2 Airline score (56.5% vs 45.5%)
Higher Tau2 Retail score (70.6% vs 63.4%)
Higher Tau2 Telecom score (65.8% vs 23.5%)

Detailed Comparison

AI Model Comparison Table
Feature
OpenAI
GPT-4o
Moonshot AI
Kimi K2-Instruct-0905

FAQ

Common questions about GPT-4o vs Kimi K2-Instruct-0905.

Which is better, GPT-4o or Kimi K2-Instruct-0905?

Kimi K2-Instruct-0905 significantly outperforms across most benchmarks. GPT-4o is made by OpenAI 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 GPT-4o compare to Kimi K2-Instruct-0905 in benchmarks?

GPT-4o scores AI2D: 94.2%, DocVQA: 92.8%, ChartQA: 85.7%, MMLU: 85.7%, CharXiv-D: 85.3%. 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 GPT-4o and Kimi K2-Instruct-0905?

GPT-4o supports 128K 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 GPT-4o 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 GPT-4o and Kimi K2-Instruct-0905?

GPT-4o is developed by OpenAI and Kimi K2-Instruct-0905 is developed by Moonshot AI.