benchlm.ai

GPT-OSS 20B 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 22 (46 point difference).o3-pro wins 4 out of 4 categories.

GPT-OSS 20B

CreatorOpenAI
TypeOpen Weight
Context128K
Score22

o3-pro

CreatorOpenAI
TypeProprietary
Context200K
Score68

Knowledge

o3-pro

GPT-OSS 20B

28.8

o3-pro

87.3

31
MMLU
88
30
GPQA
89
28
SuperGPQA
87
26
OpenBookQA
85

Coding

o3-pro

GPT-OSS 20B

23

o3-pro

80

23
HumanEval
80

Mathematics

o3-pro

GPT-OSS 20B

30

o3-pro

89

31
AIME 2023
90
33
AIME 2024
92
32
AIME 2025
91
27
HMMT Feb 2023
86
29
HMMT Feb 2024
88
28
HMMT Feb 2025
87
30
BRUMO 2025
89

Reasoning

o3-pro

GPT-OSS 20B

28

o3-pro

85

29
SimpleQA
86
27
MuSR
84

Frequently Asked Questions

Which is better, GPT-OSS 20B or o3-pro?

o3-pro scores higher overall with 68 vs 22, a difference of 46 points across all benchmarks.

Which is better for knowledge tasks, GPT-OSS 20B or o3-pro?

o3-pro leads in knowledge tasks with an average score of 87.3 vs 28.8.

Which is better for coding, GPT-OSS 20B or o3-pro?

o3-pro leads in coding with an average score of 80 vs 23.

Which is better for math, GPT-OSS 20B or o3-pro?

o3-pro leads in math with an average score of 89 vs 30.

Which is better for reasoning, GPT-OSS 20B or o3-pro?

o3-pro leads in reasoning with an average score of 85 vs 28.

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