GPT-5.4 Pro vs GPT-5.3 Codex

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

GPT-5.4 Pro has the cleaner overall profile here, landing at 94 versus 92. It is a real lead, but still close enough that category-level strengths matter more than the headline number.

GPT-5.4 Pro's sharpest advantage is in instruction following, where it averages 97 against 93. The single biggest benchmark swing on the page is HLE, 50 to 44.

GPT-5.4 Pro is also the more expensive model on tokens at $30.00 input / $180.00 output per 1M tokens, versus $2.50 input / $10.00 output per 1M tokens for GPT-5.3 Codex. That is roughly 18.0x on output cost alone. GPT-5.4 Pro gives you the larger context window at 1.05M, compared with 400K for GPT-5.3 Codex.

Quick Verdict

Pick GPT-5.4 Pro if you want the stronger benchmark profile. GPT-5.3 Codex only becomes the better choice if you want the cheaper token bill.

Knowledge

GPT-5.4 Pro

GPT-5.4 Pro

88.8

GPT-5.3 Codex

86.3

99
MMLU
99
99
GPQA
97
97
SuperGPQA
95
94
OpenBookQA
93
94
MMLU-Pro
90
50
HLE
44

Coding

GPT-5.4 Pro

GPT-5.4 Pro

89

GPT-5.3 Codex

88.3

95
HumanEval
95
86
SWE-bench Verified
85
86
LiveCodeBench
85

Mathematics

GPT-5.4 Pro

GPT-5.4 Pro

98

GPT-5.3 Codex

97.4

99
AIME 2023
99
99
AIME 2024
99
99
AIME 2025
98
96
HMMT Feb 2023
95
98
HMMT Feb 2024
97
97
HMMT Feb 2025
96
97
BRUMO 2025
96
99
MATH-500
99

Reasoning

GPT-5.4 Pro

GPT-5.4 Pro

96.7

GPT-5.3 Codex

95.3

97
SimpleQA
95
95
MuSR
93
98
BBH
98

Instruction Following

GPT-5.4 Pro

GPT-5.4 Pro

97

GPT-5.3 Codex

93

97
IFEval
93

Multilingual

GPT-5.4 Pro

GPT-5.4 Pro

97

GPT-5.3 Codex

96

97
MGSM
96

Frequently Asked Questions

Which is better, GPT-5.4 Pro or GPT-5.3 Codex?

GPT-5.4 Pro is ahead overall, 94 to 92. The biggest single separator in this matchup is HLE, where the scores are 50 and 44.

Which is better for knowledge tasks, GPT-5.4 Pro or GPT-5.3 Codex?

GPT-5.4 Pro has the edge for knowledge tasks in this comparison, averaging 88.8 versus 86.3. Inside this category, HLE is the benchmark that creates the most daylight between them.

Which is better for coding, GPT-5.4 Pro or GPT-5.3 Codex?

GPT-5.4 Pro has the edge for coding in this comparison, averaging 89 versus 88.3. Inside this category, SWE-bench Verified is the benchmark that creates the most daylight between them.

Which is better for math, GPT-5.4 Pro or GPT-5.3 Codex?

GPT-5.4 Pro has the edge for math in this comparison, averaging 98 versus 97.4. Inside this category, AIME 2025 is the benchmark that creates the most daylight between them.

Which is better for reasoning, GPT-5.4 Pro or GPT-5.3 Codex?

GPT-5.4 Pro has the edge for reasoning in this comparison, averaging 96.7 versus 95.3. Inside this category, SimpleQA is the benchmark that creates the most daylight between them.

Which is better for instruction following, GPT-5.4 Pro or GPT-5.3 Codex?

GPT-5.4 Pro has the edge for instruction following in this comparison, averaging 97 versus 93. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Which is better for multilingual tasks, GPT-5.4 Pro or GPT-5.3 Codex?

GPT-5.4 Pro has the edge for multilingual tasks in this comparison, averaging 97 versus 96. Inside this category, MGSM is the benchmark that creates the most daylight between them.

Last updated: March 9, 2026

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