Gemini 3 Flash vs o3-mini

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

Gemini 3 Flash is clearly ahead on the aggregate, 65 to 56. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

o3-mini is also the more expensive model on tokens at $1.10 input / $4.40 output per 1M tokens, versus $0.50 input / $3.00 output per 1M tokens for Gemini 3 Flash. o3-mini is the reasoning model in the pair, while Gemini 3 Flash 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. Gemini 3 Flash gives you the larger context window at 1M, compared with 200K for o3-mini.

Quick Verdict

Pick Gemini 3 Flash if you want the stronger benchmark profile. o3-mini only becomes the better choice if knowledge is the priority or you want the stronger reasoning-first profile.

Knowledge

o3-mini

Gemini 3 Flash

58.2

o3-mini

82.1

70
MMLU
86.9
69
GPQA
77.2
67
SuperGPQA
-
65
OpenBookQA
-
72
MMLU-Pro
-
6
HLE
-

Coding

o3-mini

Gemini 3 Flash

47.3

o3-mini

49.3

62
HumanEval
-
44
SWE-bench Verified
49.3
36
LiveCodeBench
-

Mathematics

o3-mini

Gemini 3 Flash

70.4

o3-mini

87.3

70
AIME 2023
-
72
AIME 2024
87.3
71
AIME 2025
-
66
HMMT Feb 2023
-
68
HMMT Feb 2024
-
67
HMMT Feb 2025
-
69
BRUMO 2025
-
80
MATH-500
-

Reasoning

Gemini 3 Flash
67
SimpleQA
-
65
MuSR
-
84
BBH
-

Instruction Following

o3-mini

Gemini 3 Flash

85

o3-mini

93.9

85
IFEval
93.9

Multilingual

Gemini 3 Flash
85
MGSM
-

Frequently Asked Questions

Which is better, Gemini 3 Flash or o3-mini?

Gemini 3 Flash is ahead overall, 65 to 56. The biggest single separator in this matchup is MMLU, where the scores are 70 and 86.9.

Which is better for knowledge tasks, Gemini 3 Flash or o3-mini?

o3-mini has the edge for knowledge tasks in this comparison, averaging 82.1 versus 58.2. Inside this category, MMLU is the benchmark that creates the most daylight between them.

Which is better for coding, Gemini 3 Flash or o3-mini?

o3-mini has the edge for coding in this comparison, averaging 49.3 versus 47.3. Inside this category, SWE-bench Verified is the benchmark that creates the most daylight between them.

Which is better for math, Gemini 3 Flash or o3-mini?

o3-mini has the edge for math in this comparison, averaging 87.3 versus 70.4. Inside this category, AIME 2024 is the benchmark that creates the most daylight between them.

Which is better for instruction following, Gemini 3 Flash or o3-mini?

o3-mini has the edge for instruction following in this comparison, averaging 93.9 versus 85. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Last updated: March 9, 2026

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