benchlm.ai

Claude Haiku 4.5 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 57 (25 point difference).GPT-5.2-Codex wins 4 out of 4 categories.

Claude Haiku 4.5

CreatorAnthropic
TypeProprietary
Context200K
Score57

GPT-5.2-Codex

CreatorOpenAI
TypeProprietary
Context400K
Score82

Knowledge

GPT-5.2-Codex

Claude Haiku 4.5

65.8

GPT-5.2-Codex

96

68
MMLU
99
67
GPQA
97
65
SuperGPQA
95
63
OpenBookQA
93

Coding

GPT-5.2-Codex

Claude Haiku 4.5

60

GPT-5.2-Codex

95

60
HumanEval
95

Mathematics

GPT-5.2-Codex

Claude Haiku 4.5

67

GPT-5.2-Codex

97.1

68
AIME 2023
99
70
AIME 2024
99
69
AIME 2025
98
64
HMMT Feb 2023
95
66
HMMT Feb 2024
97
65
HMMT Feb 2025
96
67
BRUMO 2025
96

Reasoning

GPT-5.2-Codex

Claude Haiku 4.5

64

GPT-5.2-Codex

94

65
SimpleQA
95
63
MuSR
93

Frequently Asked Questions

Which is better, Claude Haiku 4.5 or GPT-5.2-Codex?

GPT-5.2-Codex scores higher overall with 82 vs 57, a difference of 25 points across all benchmarks.

Which is better for knowledge tasks, Claude Haiku 4.5 or GPT-5.2-Codex?

GPT-5.2-Codex leads in knowledge tasks with an average score of 96 vs 65.8.

Which is better for coding, Claude Haiku 4.5 or GPT-5.2-Codex?

GPT-5.2-Codex leads in coding with an average score of 95 vs 60.

Which is better for math, Claude Haiku 4.5 or GPT-5.2-Codex?

GPT-5.2-Codex leads in math with an average score of 97.1 vs 67.

Which is better for reasoning, Claude Haiku 4.5 or GPT-5.2-Codex?

GPT-5.2-Codex leads in reasoning with an average score of 94 vs 64.

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