GPT-5.1-Codex-Max vs o1-pro

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

GPT-5.1-Codex-Max is clearly ahead on the aggregate, 87 to 33. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

GPT-5.1-Codex-Max's sharpest advantage is in mathematics, where it averages 96.6 against 86. The single biggest benchmark swing on the page is GPQA, 96 to 79.

o1-pro is also the more expensive model on tokens at $150.00 input / $600.00 output per 1M tokens, versus $2.00 input / $8.00 output per 1M tokens for GPT-5.1-Codex-Max. That is roughly 75.0x on output cost alone. GPT-5.1-Codex-Max gives you the larger context window at 400K, compared with 200K for o1-pro.

Quick Verdict

Pick GPT-5.1-Codex-Max if you want the stronger benchmark profile. o1-pro only becomes the better choice if its workflow or ecosystem matters more than the raw scoreboard.

Knowledge

GPT-5.1-Codex-Max

GPT-5.1-Codex-Max

81.5

o1-pro

79

98
MMLU
-
96
GPQA
79
94
SuperGPQA
-
92
OpenBookQA
-
82
MMLU-Pro
-
27
HLE
-

Coding

GPT-5.1-Codex-Max
94
HumanEval
-
75
SWE-bench Verified
-
67
LiveCodeBench
-

Mathematics

GPT-5.1-Codex-Max

GPT-5.1-Codex-Max

96.6

o1-pro

86

99
AIME 2023
-
99
AIME 2024
86
98
AIME 2025
-
95
HMMT Feb 2023
-
97
HMMT Feb 2024
-
96
HMMT Feb 2025
-
96
BRUMO 2025
-
93
MATH-500
-

Reasoning

GPT-5.1-Codex-Max
94
SimpleQA
-
92
MuSR
-
92
BBH
-

Instruction Following

GPT-5.1-Codex-Max
91
IFEval
-

Multilingual

GPT-5.1-Codex-Max
89
MGSM
-

Frequently Asked Questions

Which is better, GPT-5.1-Codex-Max or o1-pro?

GPT-5.1-Codex-Max is ahead overall, 87 to 33. The biggest single separator in this matchup is GPQA, where the scores are 96 and 79.

Which is better for knowledge tasks, GPT-5.1-Codex-Max or o1-pro?

GPT-5.1-Codex-Max has the edge for knowledge tasks in this comparison, averaging 81.5 versus 79. Inside this category, GPQA is the benchmark that creates the most daylight between them.

Which is better for math, GPT-5.1-Codex-Max or o1-pro?

GPT-5.1-Codex-Max has the edge for math in this comparison, averaging 96.6 versus 86. Inside this category, AIME 2024 is the benchmark that creates the most daylight between them.

Last updated: March 9, 2026

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