benchlm.ai

Claude 3 Haiku vs GPT-5.2-Codex

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

Quick Verdict

GPT-5.2-Codex wins overall with a score of 82 vs 46 (36 point difference).GPT-5.2-Codex wins 4 out of 4 categories.

Claude 3 Haiku

CreatorAnthropic
TypeProprietary
Context200K
Score46

GPT-5.2-Codex

CreatorOpenAI
TypeProprietary
Context400K
Score82

Knowledge

GPT-5.2-Codex

Claude 3 Haiku

54.5

GPT-5.2-Codex

96

56
MMLU
99
56
GPQA
97
54
SuperGPQA
95
52
OpenBookQA
93

Coding

GPT-5.2-Codex

Claude 3 Haiku

48

GPT-5.2-Codex

95

48
HumanEval
95

Mathematics

GPT-5.2-Codex

Claude 3 Haiku

55

GPT-5.2-Codex

97.1

56
AIME 2023
99
58
AIME 2024
99
57
AIME 2025
98
52
HMMT Feb 2023
95
54
HMMT Feb 2024
97
53
HMMT Feb 2025
96
55
BRUMO 2025
96

Reasoning

GPT-5.2-Codex

Claude 3 Haiku

53

GPT-5.2-Codex

94

54
SimpleQA
95
52
MuSR
93

Frequently Asked Questions

Which is better, Claude 3 Haiku or GPT-5.2-Codex?

GPT-5.2-Codex scores higher overall with 82 vs 46, a difference of 36 points across all benchmarks.

Which is better for knowledge tasks, Claude 3 Haiku or GPT-5.2-Codex?

GPT-5.2-Codex leads in knowledge tasks with an average score of 96 vs 54.5.

Which is better for coding, Claude 3 Haiku or GPT-5.2-Codex?

GPT-5.2-Codex leads in coding with an average score of 95 vs 48.

Which is better for math, Claude 3 Haiku or GPT-5.2-Codex?

GPT-5.2-Codex leads in math with an average score of 97.1 vs 55.

Which is better for reasoning, Claude 3 Haiku or GPT-5.2-Codex?

GPT-5.2-Codex leads in reasoning with an average score of 94 vs 53.

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