Claude Opus 4.5 vs GPT OSS 20B Comparison

Comparing Claude Opus 4.5 and GPT OSS 20B across benchmarks, pricing, and capabilities.

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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 20B is better at 0 benchmarks.

Claude Opus 4.5 significantly outperforms across most benchmarks.

Sun Mar 15 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

GPT OSS 20B costs less

For input processing, Claude Opus 4.5 ($5.00/1M tokens) is 100.0x more expensive than GPT OSS 20B ($0.05/1M tokens).

For output processing, Claude Opus 4.5 ($25.00/1M tokens) is 125.0x more expensive than GPT OSS 20B ($0.20/1M tokens).

In conclusion, Claude Opus 4.5 is more expensive than GPT OSS 20B.*

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

Lowest available price from all providers

Sun Mar 15 2026 • llm-stats.com

Claude Opus 4.5

Input tokens$5.00

Output tokens$25.00

Best providerAnthropic

GPT OSS 20B

Input tokens$0.05

Output tokens$0.20

Best providerNovita

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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 20B's 131,072 tokens. Claude Opus 4.5 can generate longer responses up to 64,000 tokens, while GPT OSS 20B is limited to 32,768 tokens.

Claude Opus 4.5

Input200,000 tokens

Output64,000 tokens

GPT OSS 20B

Input131,072 tokens

Output32,768 tokens

Sun Mar 15 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Claude Opus 4.5 supports multimodal inputs, whereas GPT OSS 20B 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 20B

Text

Images

Audio

Video

License

Usage and distribution terms

Claude Opus 4.5 is licensed under a proprietary license, while GPT OSS 20B 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 20B

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 20B was released on 2025-08-05.

Claude Opus 4.5 is 4 months newer than GPT OSS 20B.

Claude Opus 4.5

Nov 24, 2025

3 months ago

3mo newer

GPT OSS 20B

Aug 5, 2025

7 months ago

Knowledge Cutoff

When training data ends

Claude Opus 4.5 has a documented knowledge cutoff of 2025-03-31, while GPT OSS 20B'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 20B's cutoff date.

Claude Opus 4.5

Mar 2025

GPT OSS 20B

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Provider Availability

Claude Opus 4.5 is available from Anthropic. GPT OSS 20B is available from Novita, Fireworks, Groq, OpenAI. The availability of providers can affect quality of the model and reliability.