GPT-5 mini vs Seed 1.6 Flash

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

GPT-5 mini is clearly ahead on the aggregate, 69 to 56. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

GPT-5 mini's sharpest advantage is in mathematics, where it averages 87.2 against 67.1. The single biggest benchmark swing on the page is AIME 2023, 90 to 64.

Seed 1.6 Flash gives you the larger context window at 256K, compared with 128K for GPT-5 mini.

Quick Verdict

Pick GPT-5 mini if you want the stronger benchmark profile. Seed 1.6 Flash only becomes the better choice if you need the larger 256K context window.

Agentic

GPT-5 mini

GPT-5 mini

65.7

Seed 1.6 Flash

54.5

68
Terminal-Bench 2.0
52
70
BrowseComp
62
60
OSWorld-Verified
52

Coding

GPT-5 mini

GPT-5 mini

42.8

Seed 1.6 Flash

27.6

80
HumanEval
59
41
SWE-bench Verified
24
37
LiveCodeBench
25
49
SWE-bench Pro
31

Multimodal & Grounded

GPT-5 mini

GPT-5 mini

83.8

Seed 1.6 Flash

73.1

86
MMMU-Pro
74
81
OfficeQA Pro
72

Reasoning

GPT-5 mini

GPT-5 mini

81.8

Seed 1.6 Flash

66.8

84
SimpleQA
61
82
MuSR
59
87
BBH
75
80
LongBench v2
70
79
MRCRv2
74

Knowledge

GPT-5 mini

GPT-5 mini

62.8

Seed 1.6 Flash

47.3

88
MMLU
65
86
GPQA
64
84
SuperGPQA
62
82
OpenBookQA
60
73
MMLU-Pro
65
16
HLE
3
75
FrontierScience
57

Instruction Following

GPT-5 mini

GPT-5 mini

82

Seed 1.6 Flash

81

82
IFEval
81

Multilingual

GPT-5 mini

GPT-5 mini

80.1

Seed 1.6 Flash

72.8

82
MGSM
76
79
MMLU-ProX
71

Mathematics

GPT-5 mini

GPT-5 mini

87.2

Seed 1.6 Flash

67.1

90
AIME 2023
64
92
AIME 2024
66
91
AIME 2025
65
86
HMMT Feb 2023
60
88
HMMT Feb 2024
62
87
HMMT Feb 2025
61
89
BRUMO 2025
63
85
MATH-500
72

Frequently Asked Questions

Which is better, GPT-5 mini or Seed 1.6 Flash?

GPT-5 mini is ahead overall, 69 to 56. The biggest single separator in this matchup is AIME 2023, where the scores are 90 and 64.

Which is better for knowledge tasks, GPT-5 mini or Seed 1.6 Flash?

GPT-5 mini has the edge for knowledge tasks in this comparison, averaging 62.8 versus 47.3. Inside this category, MMLU is the benchmark that creates the most daylight between them.

Which is better for coding, GPT-5 mini or Seed 1.6 Flash?

GPT-5 mini has the edge for coding in this comparison, averaging 42.8 versus 27.6. Inside this category, HumanEval is the benchmark that creates the most daylight between them.

Which is better for math, GPT-5 mini or Seed 1.6 Flash?

GPT-5 mini has the edge for math in this comparison, averaging 87.2 versus 67.1. Inside this category, AIME 2023 is the benchmark that creates the most daylight between them.

Which is better for reasoning, GPT-5 mini or Seed 1.6 Flash?

GPT-5 mini has the edge for reasoning in this comparison, averaging 81.8 versus 66.8. Inside this category, SimpleQA is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, GPT-5 mini or Seed 1.6 Flash?

GPT-5 mini has the edge for agentic tasks in this comparison, averaging 65.7 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, GPT-5 mini or Seed 1.6 Flash?

GPT-5 mini has the edge for multimodal and grounded tasks in this comparison, averaging 83.8 versus 73.1. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.

Which is better for instruction following, GPT-5 mini or Seed 1.6 Flash?

GPT-5 mini has the edge for instruction following in this comparison, averaging 82 versus 81. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Which is better for multilingual tasks, GPT-5 mini or Seed 1.6 Flash?

GPT-5 mini has the edge for multilingual tasks in this comparison, averaging 80.1 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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