Claude Opus 5 vs GPT OSS 120B
Compare Claude Opus 5 by Anthropic against GPT OSS 120B by OpenAI, context windows of 1.0M vs 131K, tested across 53 shared challenges.
Our Verdict
Claude Opus 5
GPT OSS 120BRunner-up
No community votes yet. On paper, Claude Opus 5 has the edge — newer, bigger context window.
GPT OSS 120B is 31x cheaper per token — worth considering if cost matters.
Too close to call
API pricing
Cost per 1M tokens
Claude Opus 5
Input
$5.00
Output
$25.00
GPT OSS 120B
Input
$0.18
28× cheaper
Output
$0.80
31× cheaper
GPT OSS 120B is cheaper on both — 28× input, 31× output
Writing DNA
Style Comparison
Similarity
64%
GPT OSS 120B uses 9.0x more emoji
Claude Opus 5
GPT OSS 120B
54%Vocabulary52%
21wSentence Length19w
0.40Hedging0.28
3.9Bold7.4
1.9Lists1.8
0.02Emoji0.15
0.71Headings0.73
0.05Transitions0.17
Based on 27 + 21 text responses
Research
What we learned reading every model
FAQ
