benchlm.ai

Claude Haiku 4.5 vs GPT-OSS 120B

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

Quick Verdict

Claude Haiku 4.5 wins overall with a score of 57 vs 42 (15 point difference).Claude Haiku 4.5 wins 4 out of 4 categories.

Claude Haiku 4.5

CreatorAnthropic
TypeProprietary
Context200K
Score57

GPT-OSS 120B

CreatorOpenAI
TypeOpen Weight
Context128K
Score42

Knowledge

Claude Haiku 4.5

Claude Haiku 4.5

65.8

GPT-OSS 120B

48.8

68
MMLU
51
67
GPQA
50
65
SuperGPQA
48
63
OpenBookQA
46

Coding

Claude Haiku 4.5

Claude Haiku 4.5

60

GPT-OSS 120B

43

60
HumanEval
43

Mathematics

Claude Haiku 4.5

Claude Haiku 4.5

67

GPT-OSS 120B

50

68
AIME 2023
51
70
AIME 2024
53
69
AIME 2025
52
64
HMMT Feb 2023
47
66
HMMT Feb 2024
49
65
HMMT Feb 2025
48
67
BRUMO 2025
50

Reasoning

Claude Haiku 4.5

Claude Haiku 4.5

64

GPT-OSS 120B

48

65
SimpleQA
49
63
MuSR
47

Frequently Asked Questions

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

Claude Haiku 4.5 scores higher overall with 57 vs 42, a difference of 15 points across all benchmarks.

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

Claude Haiku 4.5 leads in knowledge tasks with an average score of 65.8 vs 48.8.

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

Claude Haiku 4.5 leads in coding with an average score of 60 vs 43.

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

Claude Haiku 4.5 leads in math with an average score of 67 vs 50.

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

Claude Haiku 4.5 leads in reasoning with an average score of 64 vs 48.

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