benchlm.ai

Claude Haiku 4.5 vs GPT-OSS 20B

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 22 (35 point difference).Claude Haiku 4.5 wins 4 out of 4 categories.

Claude Haiku 4.5

CreatorAnthropic
TypeProprietary
Context200K
Score57

GPT-OSS 20B

CreatorOpenAI
TypeOpen Weight
Context128K
Score22

Knowledge

Claude Haiku 4.5

Claude Haiku 4.5

65.8

GPT-OSS 20B

28.8

68
MMLU
31
67
GPQA
30
65
SuperGPQA
28
63
OpenBookQA
26

Coding

Claude Haiku 4.5

Claude Haiku 4.5

60

GPT-OSS 20B

23

60
HumanEval
23

Mathematics

Claude Haiku 4.5

Claude Haiku 4.5

67

GPT-OSS 20B

30

68
AIME 2023
31
70
AIME 2024
33
69
AIME 2025
32
64
HMMT Feb 2023
27
66
HMMT Feb 2024
29
65
HMMT Feb 2025
28
67
BRUMO 2025
30

Reasoning

Claude Haiku 4.5

Claude Haiku 4.5

64

GPT-OSS 20B

28

65
SimpleQA
29
63
MuSR
27

Frequently Asked Questions

Which is better, Claude Haiku 4.5 or GPT-OSS 20B?

Claude Haiku 4.5 scores higher overall with 57 vs 22, a difference of 35 points across all benchmarks.

Which is better for knowledge tasks, Claude Haiku 4.5 or GPT-OSS 20B?

Claude Haiku 4.5 leads in knowledge tasks with an average score of 65.8 vs 28.8.

Which is better for coding, Claude Haiku 4.5 or GPT-OSS 20B?

Claude Haiku 4.5 leads in coding with an average score of 60 vs 23.

Which is better for math, Claude Haiku 4.5 or GPT-OSS 20B?

Claude Haiku 4.5 leads in math with an average score of 67 vs 30.

Which is better for reasoning, Claude Haiku 4.5 or GPT-OSS 20B?

Claude Haiku 4.5 leads in reasoning with an average score of 64 vs 28.

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