Model Comparison

Claude Opus 4.5 vs GPT OSS 120B

Claude Opus 4.5 significantly outperforms across most benchmarks. GPT OSS 120B is 55.6x cheaper per token.

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Performance Benchmarks

Comparative analysis across standard metrics

1 benchmarks

Claude Opus 4.5 outperforms in 1 benchmarks (GPQA), while GPT OSS 120B is better at 0 benchmarks.

Claude Opus 4.5 significantly outperforms across most benchmarks.

Thu May 14 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

GPT OSS 120B costs less

For input processing, Claude Opus 4.5 ($5.00/1M tokens) is 55.6x more expensive than GPT OSS 120B ($0.09/1M tokens).

For output processing, Claude Opus 4.5 ($25.00/1M tokens) is 55.6x more expensive than GPT OSS 120B ($0.45/1M tokens).

In conclusion, Claude Opus 4.5 is more expensive than GPT OSS 120B.*

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

Lowest available price from all providers

Thu May 14 2026 • llm-stats.com

Claude Opus 4.5

Input tokens$5.00

Output tokens$25.00

Best providerAnthropic

GPT OSS 120B

Input tokens$0.09

Output tokens$0.45

Best providerDeepinfra

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Context Window

Maximum input and output token capacity

Claude Opus 4.5 accepts 200,000 input tokens compared to GPT OSS 120B's 131,072 tokens. GPT OSS 120B can generate longer responses up to 131,072 tokens, while Claude Opus 4.5 is limited to 64,000 tokens.

Claude Opus 4.5

Input200,000 tokens

Output64,000 tokens

GPT OSS 120B

Input131,072 tokens

Output131,072 tokens

Thu May 14 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Claude Opus 4.5 supports multimodal inputs, whereas GPT OSS 120B does not.

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

Claude Opus 4.5

Text

Images

Audio

Video

GPT OSS 120B

Text

Images

Audio

Video

License

Usage and distribution terms

Claude Opus 4.5 is licensed under a proprietary license, while GPT OSS 120B uses Apache 2.0.

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

Claude Opus 4.5

Proprietary

Closed source

GPT OSS 120B

Apache 2.0

Open weights

Release Timeline

When each model was launched

Claude Opus 4.5 was released on 2025-11-24, while GPT OSS 120B was released on 2025-08-05.

Claude Opus 4.5 is 4 months newer than GPT OSS 120B.

Claude Opus 4.5

Nov 24, 2025

5 months ago

3mo newer

GPT OSS 120B

Aug 5, 2025

9 months ago

Knowledge Cutoff

When training data ends

Claude Opus 4.5 has a documented knowledge cutoff of 2025-03-31, while GPT OSS 120B's cutoff date is not specified.

We can confirm Claude Opus 4.5's training data extends to 2025-03-31, but cannot make a direct comparison without GPT OSS 120B's cutoff date.

Claude Opus 4.5

Mar 2025

GPT OSS 120B

—

Provider Availability

Claude Opus 4.5 is available from Anthropic. GPT OSS 120B is available from DeepInfra, Novita, OpenAI, Fireworks, Groq.

Claude Opus 4.5

Anthropic

Input Price:Input: $5.00/1MOutput Price:Output: $25.00/1M

GPT OSS 120B

Deepinfra

Input Price:Input: $0.09/1MOutput Price:Output: $0.45/1M

Novita

Input Price:Input: $0.10/1MOutput Price:Output: $0.50/1M

OpenAI

Input Price:Input: $0.10/1MOutput Price:Output: $0.50/1M

Fireworks

Input Price:Input: $0.15/1MOutput Price:Output: $0.60/1M

Groq

Input Price:Input: $0.15/1MOutput Price:Output: $0.60/1M

* Prices shown are per million tokens

Outputs Comparison

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Key Takeaways

Claude Opus 4.5

View details

Anthropic

Larger context window (200,000 tokens)

Supports multimodal inputs

Higher GPQA score (87.0% vs 80.1%)

GPT OSS 120B

View details

OpenAI

Less expensive input tokens

Less expensive output tokens

Has open weights

Detailed Comparison

AI Model Comparison Table
Feature	Claude Opus 4.5	GPT OSS 120B

FAQ

Common questions about Claude Opus 4.5 vs GPT OSS 120B.

Which is better, Claude Opus 4.5 or GPT OSS 120B?

Claude Opus 4.5 significantly outperforms across most benchmarks. Claude Opus 4.5 is made by Anthropic and GPT OSS 120B is made by OpenAI. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does Claude Opus 4.5 compare to GPT OSS 120B in benchmarks?

Claude Opus 4.5 scores Tau2 Telecom: 98.2%, MMMLU: 90.8%, Tau2 Retail: 88.9%, GPQA: 87.0%, SWE-Bench Verified: 80.9%. GPT OSS 120B scores MMLU: 90.0%, CodeForces: 82.1%, GPQA: 80.1%, TAU-bench Retail: 67.8%, HealthBench: 57.6%.

Is Claude Opus 4.5 cheaper than GPT OSS 120B?

GPT OSS 120B is 55.6x cheaper for input tokens. Claude Opus 4.5 costs $5.00/M input and $25.00/M output via anthropic. GPT OSS 120B costs $0.09/M input and $0.45/M output via deepinfra.

What are the context window sizes for Claude Opus 4.5 and GPT OSS 120B?

Claude Opus 4.5 supports 200K tokens and GPT OSS 120B supports 131K tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Claude Opus 4.5 and GPT OSS 120B?

Key differences include context window (200K vs 131K), input pricing ($5.00 vs $0.09/M), multimodal support (yes vs no), licensing (Proprietary vs Apache 2.0). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Opus 4.5 and GPT OSS 120B?

Claude Opus 4.5 is developed by Anthropic and GPT OSS 120B is developed by OpenAI.