o3 vs Seed 1.6 Flash

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

o3 is clearly ahead on the aggregate, 70 to 56. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

o3's sharpest advantage is in coding, where it averages 49.1 against 27.6. The single biggest benchmark swing on the page is SWE-bench Pro, 58 to 31. Seed 1.6 Flash does hit back in multimodal & grounded, so the answer changes if that is the part of the workload you care about most.

o3 is also the more expensive model on tokens at $10.00 input / $40.00 output per 1M tokens, versus $0.08 input / $0.30 output per 1M tokens for Seed 1.6 Flash. That is roughly 133.3x on output cost alone. Seed 1.6 Flash gives you the larger context window at 256K, compared with 200K for o3.

Quick Verdict

Pick o3 if you want the stronger benchmark profile. Seed 1.6 Flash only becomes the better choice if multimodal & grounded is the priority or you want the cheaper token bill.

Agentic

o3

o3

69.9

Seed 1.6 Flash

54.5

71
Terminal-Bench 2.0
52
75
BrowseComp
62
65
OSWorld-Verified
52

Coding

o3

o3

49.1

Seed 1.6 Flash

27.6

78
HumanEval
59
50
SWE-bench Verified
24
40
LiveCodeBench
25
58
SWE-bench Pro
31

Multimodal & Grounded

Seed 1.6 Flash

o3

72.3

Seed 1.6 Flash

73.1

70
MMMU-Pro
74
75
OfficeQA Pro
72

Reasoning

o3

o3

82.6

Seed 1.6 Flash

66.8

84
SimpleQA
61
82
MuSR
59
86
BBH
75
82
LongBench v2
70
81
MRCRv2
74

Knowledge

o3

o3

66

Seed 1.6 Flash

47.3

86
MMLU
65
87
GPQA
64
85
SuperGPQA
62
83
OpenBookQA
60
75
MMLU-Pro
65
24
HLE
3
77
FrontierScience
57

Instruction Following

o3

o3

85

Seed 1.6 Flash

81

85
IFEval
81

Multilingual

o3

o3

81.1

Seed 1.6 Flash

72.8

83
MGSM
76
80
MMLU-ProX
71

Mathematics

o3

o3

87.5

Seed 1.6 Flash

67.1

88
AIME 2023
64
90
AIME 2024
66
89
AIME 2025
65
84
HMMT Feb 2023
60
86
HMMT Feb 2024
62
85
HMMT Feb 2025
61
87
BRUMO 2025
63
88
MATH-500
72

Frequently Asked Questions

Which is better, o3 or Seed 1.6 Flash?

o3 is ahead overall, 70 to 56. The biggest single separator in this matchup is SWE-bench Pro, where the scores are 58 and 31.

Which is better for knowledge tasks, o3 or Seed 1.6 Flash?

o3 has the edge for knowledge tasks in this comparison, averaging 66 versus 47.3. Inside this category, GPQA is the benchmark that creates the most daylight between them.

Which is better for coding, o3 or Seed 1.6 Flash?

o3 has the edge for coding in this comparison, averaging 49.1 versus 27.6. Inside this category, SWE-bench Pro is the benchmark that creates the most daylight between them.

Which is better for math, o3 or Seed 1.6 Flash?

o3 has the edge for math in this comparison, averaging 87.5 versus 67.1. Inside this category, AIME 2023 is the benchmark that creates the most daylight between them.

Which is better for reasoning, o3 or Seed 1.6 Flash?

o3 has the edge for reasoning in this comparison, averaging 82.6 versus 66.8. Inside this category, SimpleQA is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, o3 or Seed 1.6 Flash?

o3 has the edge for agentic tasks in this comparison, averaging 69.9 versus 54.5. Inside this category, Terminal-Bench 2.0 is the benchmark that creates the most daylight between them.

Which is better for multimodal and grounded tasks, o3 or Seed 1.6 Flash?

Seed 1.6 Flash has the edge for multimodal and grounded tasks in this comparison, averaging 73.1 versus 72.3. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.

Which is better for instruction following, o3 or Seed 1.6 Flash?

o3 has the edge for instruction following in this comparison, averaging 85 versus 81. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Which is better for multilingual tasks, o3 or Seed 1.6 Flash?

o3 has the edge for multilingual tasks in this comparison, averaging 81.1 versus 72.8. Inside this category, MMLU-ProX is the benchmark that creates the most daylight between them.

Last updated: March 12, 2026

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