benchlm.ai

GPT-4o vs GPT-5.3 Codex

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

Quick Verdict

GPT-5.3 Codex wins overall with a score of 85 vs 56 (29 point difference).GPT-5.3 Codex wins 4 out of 4 categories.

GPT-4o

CreatorOpenAI
TypeProprietary
Context128K
Score56

GPT-5.3 Codex

CreatorOpenAI
TypeProprietary
Context400K
Score85

Knowledge

GPT-5.3 Codex

GPT-4o

64.5

GPT-5.3 Codex

96

66
MMLU
99
66
GPQA
97
64
SuperGPQA
95
62
OpenBookQA
93

Coding

GPT-5.3 Codex

GPT-4o

58

GPT-5.3 Codex

95

58
HumanEval
95

Mathematics

GPT-5.3 Codex

GPT-4o

65

GPT-5.3 Codex

97.1

66
AIME 2023
99
68
AIME 2024
99
67
AIME 2025
98
62
HMMT Feb 2023
95
64
HMMT Feb 2024
97
63
HMMT Feb 2025
96
65
BRUMO 2025
96

Reasoning

GPT-5.3 Codex

GPT-4o

63

GPT-5.3 Codex

94

64
SimpleQA
95
62
MuSR
93

Frequently Asked Questions

Which is better, GPT-4o or GPT-5.3 Codex?

GPT-5.3 Codex scores higher overall with 85 vs 56, a difference of 29 points across all benchmarks.

Which is better for knowledge tasks, GPT-4o or GPT-5.3 Codex?

GPT-5.3 Codex leads in knowledge tasks with an average score of 96 vs 64.5.

Which is better for coding, GPT-4o or GPT-5.3 Codex?

GPT-5.3 Codex leads in coding with an average score of 95 vs 58.

Which is better for math, GPT-4o or GPT-5.3 Codex?

GPT-5.3 Codex leads in math with an average score of 97.1 vs 65.

Which is better for reasoning, GPT-4o or GPT-5.3 Codex?

GPT-5.3 Codex leads in reasoning with an average score of 94 vs 63.

Related Comparisons

GPT-4o vs GPT-5.4GPT-4o vs Gemini 3.1 ProGPT-4o vs Claude Opus 4.6GPT-4o vs Grok 4.1GPT-4o vs GPT-5.2GPT-4o vs GPT-5.2-Codex