Mercury 2 vs Seed 1.6 Flash

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

Mercury 2 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.

Mercury 2's sharpest advantage is in mathematics, where it averages 80.9 against 67.1. The single biggest benchmark swing on the page is MuSR, 82 to 59. 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.

Mercury 2 is also the more expensive model on tokens at $0.25 input / $0.75 output per 1M tokens, versus $0.08 input / $0.30 output per 1M tokens for Seed 1.6 Flash. That is roughly 2.5x on output cost alone. Seed 1.6 Flash gives you the larger context window at 256K, compared with 128K for Mercury 2.

Quick Verdict

Pick Mercury 2 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

Mercury 2

Mercury 2

63.7

Seed 1.6 Flash

54.5

63
Terminal-Bench 2.0
52
67
BrowseComp
62
62
OSWorld-Verified
52

Coding

Mercury 2

Mercury 2

41.1

Seed 1.6 Flash

27.6

75
HumanEval
59
46
SWE-bench Verified
24
38
LiveCodeBench
25
43
SWE-bench Pro
31

Multimodal & Grounded

Seed 1.6 Flash

Mercury 2

68.3

Seed 1.6 Flash

73.1

66
MMMU-Pro
74
71
OfficeQA Pro
72

Reasoning

Mercury 2

Mercury 2

80.1

Seed 1.6 Flash

66.8

82
SimpleQA
61
82
MuSR
59
87
BBH
75
77
LongBench v2
70
76
MRCRv2
74

Knowledge

Mercury 2

Mercury 2

57.2

Seed 1.6 Flash

47.3

78
MMLU
65
78
GPQA
64
76
SuperGPQA
62
74
OpenBookQA
60
72
MMLU-Pro
65
9
HLE
3
69
FrontierScience
57

Instruction Following

Mercury 2

Mercury 2

84

Seed 1.6 Flash

81

84
IFEval
81

Multilingual

Mercury 2

Mercury 2

79.7

Seed 1.6 Flash

72.8

81
MGSM
76
79
MMLU-ProX
71

Mathematics

Mercury 2

Mercury 2

80.9

Seed 1.6 Flash

67.1

81
AIME 2023
64
83
AIME 2024
66
82
AIME 2025
65
77
HMMT Feb 2023
60
79
HMMT Feb 2024
62
78
HMMT Feb 2025
61
80
BRUMO 2025
63
82
MATH-500
72

Frequently Asked Questions

Which is better, Mercury 2 or Seed 1.6 Flash?

Mercury 2 is ahead overall, 65 to 56. The biggest single separator in this matchup is MuSR, where the scores are 82 and 59.

Which is better for knowledge tasks, Mercury 2 or Seed 1.6 Flash?

Mercury 2 has the edge for knowledge tasks in this comparison, averaging 57.2 versus 47.3. Inside this category, GPQA is the benchmark that creates the most daylight between them.

Which is better for coding, Mercury 2 or Seed 1.6 Flash?

Mercury 2 has the edge for coding in this comparison, averaging 41.1 versus 27.6. Inside this category, SWE-bench Verified is the benchmark that creates the most daylight between them.

Which is better for math, Mercury 2 or Seed 1.6 Flash?

Mercury 2 has the edge for math in this comparison, averaging 80.9 versus 67.1. Inside this category, AIME 2023 is the benchmark that creates the most daylight between them.

Which is better for reasoning, Mercury 2 or Seed 1.6 Flash?

Mercury 2 has the edge for reasoning in this comparison, averaging 80.1 versus 66.8. Inside this category, MuSR is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, Mercury 2 or Seed 1.6 Flash?

Mercury 2 has the edge for agentic tasks in this comparison, averaging 63.7 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, Mercury 2 or Seed 1.6 Flash?

Seed 1.6 Flash has the edge for multimodal and grounded tasks in this comparison, averaging 73.1 versus 68.3. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.

Which is better for instruction following, Mercury 2 or Seed 1.6 Flash?

Mercury 2 has the edge for instruction following in this comparison, averaging 84 versus 81. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Which is better for multilingual tasks, Mercury 2 or Seed 1.6 Flash?

Mercury 2 has the edge for multilingual tasks in this comparison, averaging 79.7 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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