Model Comparison

GPT OSS 120B vs Kimi K2-Instruct-0905

GPT OSS 120B significantly outperforms across most benchmarks.

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Performance Benchmarks

Comparative analysis across standard metrics

3 benchmarks

GPT OSS 120B outperforms in 3 benchmarks (GPQA, Humanity's Last Exam, MMLU), while Kimi K2-Instruct-0905 is better at 0 benchmarks.

GPT OSS 120B significantly outperforms across most benchmarks.

Fri May 15 2026 • llm-stats.com

Arena Performance

Human preference votes

Model Size

Parameter count comparison

883.2B diff

Kimi K2-Instruct-0905 has 883.2B more parameters than GPT OSS 120B, making it 756.2% larger.

OpenAI
GPT OSS 120B
116.8Bparameters
Moonshot AI
Kimi K2-Instruct-0905
1.0Tparameters
116.8B
GPT OSS 120B
1000.0B
Kimi K2-Instruct-0905

Context Window

Maximum input and output token capacity

Only GPT OSS 120B specifies input context (131,072 tokens). Only GPT OSS 120B specifies output context (131,072 tokens).

OpenAI
GPT OSS 120B
Input131,072 tokens
Output131,072 tokens
Moonshot AI
Kimi K2-Instruct-0905
Input- tokens
Output- tokens
Fri May 15 2026 • llm-stats.com

License

Usage and distribution terms

GPT OSS 120B is licensed under Apache 2.0, while Kimi K2-Instruct-0905 uses MIT.

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

GPT OSS 120B

Apache 2.0

Open weights

Kimi K2-Instruct-0905

MIT

Open weights

Release Timeline

When each model was launched

GPT OSS 120B was released on 2025-08-05, while Kimi K2-Instruct-0905 was released on 2025-09-05.

Kimi K2-Instruct-0905 is 1 month newer than GPT OSS 120B.

GPT OSS 120B

Aug 5, 2025

9 months ago

Kimi K2-Instruct-0905

Sep 5, 2025

8 months ago

1mo 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 (131,072 tokens)
Higher GPQA score (80.1% vs 75.1%)
Higher Humanity's Last Exam score (14.9% vs 4.7%)
Higher MMLU score (90.0% vs 89.5%)
Moonshot AI

No standout differentiators in the data we have for this pair.

Detailed Comparison

AI Model Comparison Table
Feature
OpenAI
GPT OSS 120B
Moonshot AI
Kimi K2-Instruct-0905

FAQ

Common questions about GPT OSS 120B vs Kimi K2-Instruct-0905.

Which is better, GPT OSS 120B or Kimi K2-Instruct-0905?

GPT OSS 120B significantly outperforms across most benchmarks. GPT OSS 120B 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 OSS 120B compare to Kimi K2-Instruct-0905 in benchmarks?

GPT OSS 120B scores MMLU: 90.0%, CodeForces: 82.1%, GPQA: 80.1%, TAU-bench Retail: 67.8%, HealthBench: 57.6%. 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 OSS 120B and Kimi K2-Instruct-0905?

GPT OSS 120B supports 131K 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 OSS 120B and Kimi K2-Instruct-0905?

Key differences include licensing (Apache 2.0 vs MIT). See the full comparison above for benchmark-by-benchmark results.

Who makes GPT OSS 120B and Kimi K2-Instruct-0905?

GPT OSS 120B is developed by OpenAI and Kimi K2-Instruct-0905 is developed by Moonshot AI.