Claude 3 Opus vs GPT OSS 120B

Compare Claude 3 Opus by Anthropic against GPT OSS 120B by OpenAI, context windows of 200K vs 131K, tested across 12 shared challenges. Updated April 2026.

Which is better, Claude 3 Opus or GPT OSS 120B?

Claude 3 Opus and GPT OSS 120B are both competitive models. Claude 3 Opus costs $15/M input tokens vs $0.18/M for GPT OSS 120B. Context windows: 200K vs 131K tokens. Compare their real outputs side by side below.

Key Differences Between Claude 3 Opus and GPT OSS 120B

Claude 3 Opus is made by anthropic while GPT OSS 120B is from openai. Claude 3 Opus has a 200K token context window compared to GPT OSS 120B's 131K. On pricing, Claude 3 Opus costs $15/M input tokens vs $0.18/M for GPT OSS 120B.

Our Verdict
Claude 3 Opus
Claude 3 Opus
GPT OSS 120B
GPT OSS 120B

No community votes yet. On paper, these are closely matched - try both with your actual task to see which fits your workflow.

GPT OSS 120B is 94x cheaper per token — worth considering if cost matters.

Too close to call
Writing DNA

Style Comparison

Similarity
94%

GPT OSS 120B uses 743.4x more bold

Claude 3 Opus
GPT OSS 120B
54%Vocabulary52%
14wSentence Length19w
0.48Hedging0.28
0.0Bold7.4
3.0Lists1.8
0.00Emoji0.15
0.00Headings0.73
0.06Transitions0.17
Based on 3 + 21 text responses
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Claude 3 OpusGPT OSS 120B

279 AI models invented the same fake scientist.

We read every word. 250 models. 2.14 million words. This is what we found.

AI Hallucination Index 2026
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