GPT-5.1 vs o3-mini

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

GPT-5.1 is clearly ahead on the aggregate, 85 to 56. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

GPT-5.1's sharpest advantage is in coding, where it averages 72.7 against 49.3. The single biggest benchmark swing on the page is SWE-bench Verified, 68 to 49.3. o3-mini does hit back in instruction following, so the answer changes if that is the part of the workload you care about most.

GPT-5.1 is also the more expensive model on tokens at $1.50 input / $6.00 output per 1M tokens, versus $1.10 input / $4.40 output per 1M tokens for o3-mini.

Quick Verdict

Pick GPT-5.1 if you want the stronger benchmark profile. o3-mini only becomes the better choice if instruction following is the priority or you want the cheaper token bill.

Knowledge

o3-mini

GPT-5.1

81

o3-mini

82.1

97
MMLU
86.9
95
GPQA
77.2
93
SuperGPQA
-
91
OpenBookQA
-
83
MMLU-Pro
-
27
HLE
-

Coding

GPT-5.1

GPT-5.1

72.7

o3-mini

49.3

89
HumanEval
-
68
SWE-bench Verified
49.3
61
LiveCodeBench
-

Mathematics

GPT-5.1

GPT-5.1

96.8

o3-mini

87.3

99
AIME 2023
-
99
AIME 2024
87.3
98
AIME 2025
-
95
HMMT Feb 2023
-
97
HMMT Feb 2024
-
96
HMMT Feb 2025
-
96
BRUMO 2025
-
94
MATH-500
-

Reasoning

GPT-5.1
93
SimpleQA
-
91
MuSR
-
92
BBH
-

Instruction Following

o3-mini

GPT-5.1

89

o3-mini

93.9

89
IFEval
93.9

Multilingual

GPT-5.1
89
MGSM
-

Frequently Asked Questions

Which is better, GPT-5.1 or o3-mini?

GPT-5.1 is ahead overall, 85 to 56. The biggest single separator in this matchup is SWE-bench Verified, where the scores are 68 and 49.3.

Which is better for knowledge tasks, GPT-5.1 or o3-mini?

o3-mini has the edge for knowledge tasks in this comparison, averaging 82.1 versus 81. Inside this category, GPQA is the benchmark that creates the most daylight between them.

Which is better for coding, GPT-5.1 or o3-mini?

GPT-5.1 has the edge for coding in this comparison, averaging 72.7 versus 49.3. Inside this category, SWE-bench Verified is the benchmark that creates the most daylight between them.

Which is better for math, GPT-5.1 or o3-mini?

GPT-5.1 has the edge for math in this comparison, averaging 96.8 versus 87.3. Inside this category, AIME 2024 is the benchmark that creates the most daylight between them.

Which is better for instruction following, GPT-5.1 or o3-mini?

o3-mini has the edge for instruction following in this comparison, averaging 93.9 versus 89. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Last updated: March 9, 2026

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