Model Comparison

Claude Opus 4.5 vs GPT OSS 120B HighWhich is better in 2026?

Claude Opus 4.5 significantly outperforms across most benchmarks. GPT OSS 120B High is 50.0x cheaper per token.

Verdict: Claude Opus 4.5 vs GPT OSS 120B High — which is better?

Claude Opus 4.5 (by Anthropic) and GPT OSS 120B High (by OpenAI) 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 Opus 4.5 outperforms in 2 benchmarks (GPQA, MMMLU), while GPT OSS 120B High is better at 0 benchmarks. Claude Opus 4.5 significantly outperforms across most benchmarks.

On price, GPT OSS 120B High is roughly 50.0x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

Claude Opus 4.5 also accepts a larger context window (200,000 input tokens), making it the stronger choice for long documents and large codebases.

Choose Claude Opus 4.5 if…

  • you want the strongest raw capability — it leads on 2 of 2 shared benchmarks
  • you process long inputs — it offers a 200,000 token context window
  • you want the most recent training data — it shipped Nov 2025

Choose GPT OSS 120B High if…

  • cost matters — it's about 50.0x cheaper per token
  • you need open weights you can self-host or fine-tune
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Performance Benchmarks

Comparative analysis across standard metrics

2 benchmarks

Claude Opus 4.5 outperforms in 2 benchmarks (GPQA, MMMLU), while GPT OSS 120B High is better at 0 benchmarks.

Claude Opus 4.5 significantly outperforms across most benchmarks.

Sun Jun 07 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

GPT OSS 120B High costs less

For input processing, Claude Opus 4.5 ($5.00/1M tokens) is 50.0x more expensive than GPT OSS 120B High ($0.10/1M tokens).

For output processing, Claude Opus 4.5 ($25.00/1M tokens) is 50.0x more expensive than GPT OSS 120B High ($0.50/1M tokens).

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

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

Lowest available price from all providers
Sun Jun 07 2026 • llm-stats.com
Anthropic
Claude Opus 4.5
Input tokens$5.00
Output tokens$25.00
Best providerAnthropic
OpenAI
GPT OSS 120B High
Input tokens$0.10
Output tokens$0.50
Best providerOpenAI
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

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

Anthropic
Claude Opus 4.5
Input200,000 tokens
Output64,000 tokens
OpenAI
GPT OSS 120B High
Input131,072 tokens
Output131,072 tokens
Sun Jun 07 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Claude Opus 4.5 supports multimodal inputs, whereas GPT OSS 120B High 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 High

Text
Images
Audio
Video

License

Usage and distribution terms

Claude Opus 4.5 is licensed under a proprietary license, while GPT OSS 120B High 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 High

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 High was released on 2025-08-05.

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

Claude Opus 4.5

Nov 24, 2025

6 months ago

3mo newer
GPT OSS 120B High

Aug 5, 2025

10 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 High'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 High's cutoff date.

Claude Opus 4.5

Mar 2025

GPT OSS 120B High

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Provider Availability

Claude Opus 4.5 is available from Anthropic. GPT OSS 120B High is available from OpenAI, Fireworks.

Claude Opus 4.5

anthropic logo
Anthropic
Input Price:Input: $5.00/1MOutput Price:Output: $25.00/1M

GPT OSS 120B High

openai logo
OpenAI
Input Price:Input: $0.10/1MOutput Price:Output: $0.50/1M
fireworks logo
Fireworks
Input Price:Input: $0.15/1MOutput Price:Output: $0.60/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

Anthropic
Larger context window (200,000 tokens)
Supports multimodal inputs
Higher GPQA score (87.0% vs 80.9%)
Higher MMMLU score (90.8% vs 83.8%)
OpenAI
Less expensive input tokens
Less expensive output tokens
Has open weights

Detailed Comparison

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

FAQ

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

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

Claude Opus 4.5 significantly outperforms across most benchmarks. Claude Opus 4.5 is made by Anthropic and GPT OSS 120B High 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 High 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 High scores AIME 2025: 92.5%, MMMLU: 83.8%, LiveCodeBench v6: 81.9%, GPQA: 80.9%, MMLU-Pro: 80.7%.

Is Claude Opus 4.5 cheaper than GPT OSS 120B High?

GPT OSS 120B High is 50.0x cheaper for input tokens. Claude Opus 4.5 costs $5.00/M input and $25.00/M output via anthropic. GPT OSS 120B High costs $0.10/M input and $0.50/M output via openai.

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

Claude Opus 4.5 supports 200K tokens and GPT OSS 120B High 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 High?

Key differences include context window (200K vs 131K), input pricing ($5.00 vs $0.10/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 High?

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

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