o3-mini vs Claude 3 Opus

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

o3-mini has the cleaner overall profile here, landing at 56 versus 53. It is a real lead, but still close enough that category-level strengths matter more than the headline number.

o3-mini's sharpest advantage is in knowledge, where it averages 82.1 against 50.2. The single biggest benchmark swing on the page is SWE-bench Verified, 49.3 to 10.

o3-mini is the reasoning model in the pair, while Claude 3 Opus is not. That usually helps on harder chain-of-thought-heavy tests, but it can also mean more latency and more token spend in real use.

Quick Verdict

Pick o3-mini if you want the stronger benchmark profile. Claude 3 Opus only becomes the better choice if you would rather avoid the extra latency and token burn of a reasoning model.

Knowledge

o3-mini

o3-mini

82.1

Claude 3 Opus

50.2

86.9
MMLU
61
77.2
GPQA
61
-
SuperGPQA
59
-
OpenBookQA
57
-
MMLU-Pro
62
-
HLE
1

Coding

o3-mini

o3-mini

49.3

Claude 3 Opus

27.7

49.3
SWE-bench Verified
10
-
HumanEval
53
-
LiveCodeBench
20

Mathematics

o3-mini

o3-mini

87.3

Claude 3 Opus

61.6

87.3
AIME 2024
63
-
AIME 2023
61
-
AIME 2025
62
-
HMMT Feb 2023
57
-
HMMT Feb 2024
59
-
HMMT Feb 2025
58
-
BRUMO 2025
60
-
MATH-500
73

Reasoning

Claude 3 Opus
-
SimpleQA
59
-
MuSR
57
-
BBH
74

Instruction Following

o3-mini

o3-mini

93.9

Claude 3 Opus

77

93.9
IFEval
77

Multilingual

Claude 3 Opus
-
MGSM
73

Frequently Asked Questions

Which is better, o3-mini or Claude 3 Opus?

o3-mini is ahead overall, 56 to 53. The biggest single separator in this matchup is SWE-bench Verified, where the scores are 49.3 and 10.

Which is better for knowledge tasks, o3-mini or Claude 3 Opus?

o3-mini has the edge for knowledge tasks in this comparison, averaging 82.1 versus 50.2. Inside this category, MMLU is the benchmark that creates the most daylight between them.

Which is better for coding, o3-mini or Claude 3 Opus?

o3-mini has the edge for coding in this comparison, averaging 49.3 versus 27.7. Inside this category, SWE-bench Verified is the benchmark that creates the most daylight between them.

Which is better for math, o3-mini or Claude 3 Opus?

o3-mini has the edge for math in this comparison, averaging 87.3 versus 61.6. Inside this category, AIME 2024 is the benchmark that creates the most daylight between them.

Which is better for instruction following, o3-mini or Claude 3 Opus?

o3-mini has the edge for instruction following in this comparison, averaging 93.9 versus 77. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Last updated: March 9, 2026

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