benchlm.ai

Claude Sonnet 4.5 vs GPT-OSS 120B

Side-by-side benchmark comparison across knowledge, coding, math, and reasoning.

Quick Verdict

Claude Sonnet 4.5 wins overall with a score of 74 vs 42 (32 point difference).Claude Sonnet 4.5 wins 4 out of 4 categories.

Claude Sonnet 4.5

CreatorAnthropic
TypeProprietary
Context1M
Score74

GPT-OSS 120B

CreatorOpenAI
TypeOpen Weight
Context128K
Score42

Knowledge

Claude Sonnet 4.5

Claude Sonnet 4.5

92

GPT-OSS 120B

48.8

95
MMLU
51
93
GPQA
50
91
SuperGPQA
48
89
OpenBookQA
46

Coding

Claude Sonnet 4.5

Claude Sonnet 4.5

87

GPT-OSS 120B

43

87
HumanEval
43

Mathematics

Claude Sonnet 4.5

Claude Sonnet 4.5

96

GPT-OSS 120B

50

97
AIME 2023
51
99
AIME 2024
53
98
AIME 2025
52
93
HMMT Feb 2023
47
95
HMMT Feb 2024
49
94
HMMT Feb 2025
48
96
BRUMO 2025
50

Reasoning

Claude Sonnet 4.5

Claude Sonnet 4.5

90

GPT-OSS 120B

48

91
SimpleQA
49
89
MuSR
47

Frequently Asked Questions

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

Claude Sonnet 4.5 scores higher overall with 74 vs 42, a difference of 32 points across all benchmarks.

Which is better for knowledge tasks, Claude Sonnet 4.5 or GPT-OSS 120B?

Claude Sonnet 4.5 leads in knowledge tasks with an average score of 92 vs 48.8.

Which is better for coding, Claude Sonnet 4.5 or GPT-OSS 120B?

Claude Sonnet 4.5 leads in coding with an average score of 87 vs 43.

Which is better for math, Claude Sonnet 4.5 or GPT-OSS 120B?

Claude Sonnet 4.5 leads in math with an average score of 96 vs 50.

Which is better for reasoning, Claude Sonnet 4.5 or GPT-OSS 120B?

Claude Sonnet 4.5 leads in reasoning with an average score of 90 vs 48.

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