Kimi K2.5 (Reasoning) vs Seed 1.6 Flash

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

Kimi K2.5 (Reasoning) is clearly ahead on the aggregate, 76 to 56. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

Kimi K2.5 (Reasoning)'s sharpest advantage is in coding, where it averages 64.1 against 27.6. The single biggest benchmark swing on the page is SWE-bench Verified, 65 to 24.

Seed 1.6 Flash gives you the larger context window at 256K, compared with 128K for Kimi K2.5 (Reasoning).

Quick Verdict

Pick Kimi K2.5 (Reasoning) 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

Kimi K2.5 (Reasoning)

Kimi K2.5 (Reasoning)

73.1

Seed 1.6 Flash

54.5

75
Terminal-Bench 2.0
52
77
BrowseComp
62
68
OSWorld-Verified
52

Coding

Kimi K2.5 (Reasoning)

Kimi K2.5 (Reasoning)

64.1

Seed 1.6 Flash

27.6

84
HumanEval
59
65
SWE-bench Verified
24
58
LiveCodeBench
25
70
SWE-bench Pro
31

Multimodal & Grounded

Kimi K2.5 (Reasoning)

Kimi K2.5 (Reasoning)

74.3

Seed 1.6 Flash

73.1

72
MMMU-Pro
74
77
OfficeQA Pro
72

Reasoning

Kimi K2.5 (Reasoning)

Kimi K2.5 (Reasoning)

84.9

Seed 1.6 Flash

66.8

88
SimpleQA
61
86
MuSR
59
91
BBH
75
82
LongBench v2
70
81
MRCRv2
74

Knowledge

Kimi K2.5 (Reasoning)

Kimi K2.5 (Reasoning)

69.7

Seed 1.6 Flash

47.3

92
MMLU
65
90
GPQA
64
88
SuperGPQA
62
86
OpenBookQA
60
81
MMLU-Pro
65
27
HLE
3
80
FrontierScience
57

Instruction Following

Kimi K2.5 (Reasoning)

Kimi K2.5 (Reasoning)

91

Seed 1.6 Flash

81

91
IFEval
81

Multilingual

Kimi K2.5 (Reasoning)

Kimi K2.5 (Reasoning)

86.7

Seed 1.6 Flash

72.8

88
MGSM
76
86
MMLU-ProX
71

Mathematics

Kimi K2.5 (Reasoning)

Kimi K2.5 (Reasoning)

92.6

Seed 1.6 Flash

67.1

94
AIME 2023
64
96
AIME 2024
66
95
AIME 2025
65
90
HMMT Feb 2023
60
92
HMMT Feb 2024
62
91
HMMT Feb 2025
61
93
BRUMO 2025
63
92
MATH-500
72

Frequently Asked Questions

Which is better, Kimi K2.5 (Reasoning) or Seed 1.6 Flash?

Kimi K2.5 (Reasoning) is ahead overall, 76 to 56. The biggest single separator in this matchup is SWE-bench Verified, where the scores are 65 and 24.

Which is better for knowledge tasks, Kimi K2.5 (Reasoning) or Seed 1.6 Flash?

Kimi K2.5 (Reasoning) has the edge for knowledge tasks in this comparison, averaging 69.7 versus 47.3. Inside this category, MMLU is the benchmark that creates the most daylight between them.

Which is better for coding, Kimi K2.5 (Reasoning) or Seed 1.6 Flash?

Kimi K2.5 (Reasoning) has the edge for coding in this comparison, averaging 64.1 versus 27.6. Inside this category, SWE-bench Verified is the benchmark that creates the most daylight between them.

Which is better for math, Kimi K2.5 (Reasoning) or Seed 1.6 Flash?

Kimi K2.5 (Reasoning) has the edge for math in this comparison, averaging 92.6 versus 67.1. Inside this category, AIME 2023 is the benchmark that creates the most daylight between them.

Which is better for reasoning, Kimi K2.5 (Reasoning) or Seed 1.6 Flash?

Kimi K2.5 (Reasoning) has the edge for reasoning in this comparison, averaging 84.9 versus 66.8. Inside this category, SimpleQA is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, Kimi K2.5 (Reasoning) or Seed 1.6 Flash?

Kimi K2.5 (Reasoning) has the edge for agentic tasks in this comparison, averaging 73.1 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, Kimi K2.5 (Reasoning) or Seed 1.6 Flash?

Kimi K2.5 (Reasoning) has the edge for multimodal and grounded tasks in this comparison, averaging 74.3 versus 73.1. Inside this category, OfficeQA Pro is the benchmark that creates the most daylight between them.

Which is better for instruction following, Kimi K2.5 (Reasoning) or Seed 1.6 Flash?

Kimi K2.5 (Reasoning) has the edge for instruction following in this comparison, averaging 91 versus 81. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Which is better for multilingual tasks, Kimi K2.5 (Reasoning) or Seed 1.6 Flash?

Kimi K2.5 (Reasoning) has the edge for multilingual tasks in this comparison, averaging 86.7 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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