benchlm.ai

GPT-OSS 120B vs o3-pro

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

Quick Verdict

o3-pro wins overall with a score of 68 vs 42 (26 point difference).o3-pro wins 4 out of 4 categories.

GPT-OSS 120B

CreatorOpenAI
TypeOpen Weight
Context128K
Score42

o3-pro

CreatorOpenAI
TypeProprietary
Context200K
Score68

Knowledge

o3-pro

GPT-OSS 120B

48.8

o3-pro

87.3

51
MMLU
88
50
GPQA
89
48
SuperGPQA
87
46
OpenBookQA
85

Coding

o3-pro

GPT-OSS 120B

43

o3-pro

80

43
HumanEval
80

Mathematics

o3-pro

GPT-OSS 120B

50

o3-pro

89

51
AIME 2023
90
53
AIME 2024
92
52
AIME 2025
91
47
HMMT Feb 2023
86
49
HMMT Feb 2024
88
48
HMMT Feb 2025
87
50
BRUMO 2025
89

Reasoning

o3-pro

GPT-OSS 120B

48

o3-pro

85

49
SimpleQA
86
47
MuSR
84

Frequently Asked Questions

Which is better, GPT-OSS 120B or o3-pro?

o3-pro scores higher overall with 68 vs 42, a difference of 26 points across all benchmarks.

Which is better for knowledge tasks, GPT-OSS 120B or o3-pro?

o3-pro leads in knowledge tasks with an average score of 87.3 vs 48.8.

Which is better for coding, GPT-OSS 120B or o3-pro?

o3-pro leads in coding with an average score of 80 vs 43.

Which is better for math, GPT-OSS 120B or o3-pro?

o3-pro leads in math with an average score of 89 vs 50.

Which is better for reasoning, GPT-OSS 120B or o3-pro?

o3-pro leads in reasoning with an average score of 85 vs 48.

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