o3-mini vs Kimi K2

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

o3-mini is clearly ahead on the aggregate, 56 to 35. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

o3-mini's sharpest advantage is in knowledge, where it averages 82.1 against 28.8. The single biggest benchmark swing on the page is MMLU, 86.9 to 32.

o3-mini is the reasoning model in the pair, while Kimi K2 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. o3-mini gives you the larger context window at 200K, compared with 128K for Kimi K2.

Quick Verdict

Pick o3-mini if you want the stronger benchmark profile. Kimi K2 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

Kimi K2

28.8

86.9
MMLU
32
77.2
GPQA
31
-
SuperGPQA
29
-
OpenBookQA
27
-
MMLU-Pro
51
-
HLE
3

Coding

o3-mini

o3-mini

49.3

Kimi K2

17

49.3
SWE-bench Verified
15
-
HumanEval
24
-
LiveCodeBench
12

Mathematics

o3-mini

o3-mini

87.3

Kimi K2

34.3

87.3
AIME 2024
34
-
AIME 2023
32
-
AIME 2025
33
-
HMMT Feb 2023
28
-
HMMT Feb 2024
30
-
HMMT Feb 2025
29
-
BRUMO 2025
31
-
MATH-500
57

Reasoning

Kimi K2
-
SimpleQA
30
-
MuSR
28
-
BBH
61

Instruction Following

o3-mini

o3-mini

93.9

Kimi K2

67

93.9
IFEval
67

Multilingual

Kimi K2
-
MGSM
61

Frequently Asked Questions

Which is better, o3-mini or Kimi K2?

o3-mini is ahead overall, 56 to 35. The biggest single separator in this matchup is MMLU, where the scores are 86.9 and 32.

Which is better for knowledge tasks, o3-mini or Kimi K2?

o3-mini has the edge for knowledge tasks in this comparison, averaging 82.1 versus 28.8. Inside this category, MMLU is the benchmark that creates the most daylight between them.

Which is better for coding, o3-mini or Kimi K2?

o3-mini has the edge for coding in this comparison, averaging 49.3 versus 17. Inside this category, SWE-bench Verified is the benchmark that creates the most daylight between them.

Which is better for math, o3-mini or Kimi K2?

o3-mini has the edge for math in this comparison, averaging 87.3 versus 34.3. Inside this category, AIME 2024 is the benchmark that creates the most daylight between them.

Which is better for instruction following, o3-mini or Kimi K2?

o3-mini has the edge for instruction following in this comparison, averaging 93.9 versus 67. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Last updated: March 9, 2026

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