Claude 4 Sonnet vs Seed 1.6 Flash

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

Claude 4 Sonnet is clearly ahead on the aggregate, 64 to 56. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

Claude 4 Sonnet's sharpest advantage is in coding, where it averages 42.9 against 27.6. The single biggest benchmark swing on the page is SWE-bench Verified, 51 to 24.

Seed 1.6 Flash is the reasoning model in the pair, while Claude 4 Sonnet 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. Seed 1.6 Flash gives you the larger context window at 256K, compared with 200K for Claude 4 Sonnet.

Quick Verdict

Pick Claude 4 Sonnet if you want the stronger benchmark profile. Seed 1.6 Flash only becomes the better choice if you need the larger 256K context window or you want the stronger reasoning-first profile.

Agentic

Claude 4 Sonnet

Claude 4 Sonnet

57.9

Seed 1.6 Flash

54.5

56
Terminal-Bench 2.0
52
62
BrowseComp
62
57
OSWorld-Verified
52

Coding

Claude 4 Sonnet

Claude 4 Sonnet

42.9

Seed 1.6 Flash

27.6

65
HumanEval
59
51
SWE-bench Verified
24
36
LiveCodeBench
25
48
SWE-bench Pro
31

Multimodal & Grounded

Claude 4 Sonnet

Claude 4 Sonnet

79.7

Seed 1.6 Flash

73.1

81
MMMU-Pro
74
78
OfficeQA Pro
72

Reasoning

Claude 4 Sonnet

Claude 4 Sonnet

71.8

Seed 1.6 Flash

66.8

71
SimpleQA
61
69
MuSR
59
82
BBH
75
71
LongBench v2
70
72
MRCRv2
74

Knowledge

Claude 4 Sonnet

Claude 4 Sonnet

56.8

Seed 1.6 Flash

47.3

73
MMLU
65
73
GPQA
64
71
SuperGPQA
62
69
OpenBookQA
60
75
MMLU-Pro
65
12
HLE
3
67
FrontierScience
57

Instruction Following

Claude 4 Sonnet

Claude 4 Sonnet

83

Seed 1.6 Flash

81

83
IFEval
81

Multilingual

Claude 4 Sonnet

Claude 4 Sonnet

82.1

Seed 1.6 Flash

72.8

84
MGSM
76
81
MMLU-ProX
71

Mathematics

Claude 4 Sonnet

Claude 4 Sonnet

76.1

Seed 1.6 Flash

67.1

73
AIME 2023
64
75
AIME 2024
66
74
AIME 2025
65
69
HMMT Feb 2023
60
71
HMMT Feb 2024
62
70
HMMT Feb 2025
61
72
BRUMO 2025
63
81
MATH-500
72

Frequently Asked Questions

Which is better, Claude 4 Sonnet or Seed 1.6 Flash?

Claude 4 Sonnet is ahead overall, 64 to 56. The biggest single separator in this matchup is SWE-bench Verified, where the scores are 51 and 24.

Which is better for knowledge tasks, Claude 4 Sonnet or Seed 1.6 Flash?

Claude 4 Sonnet has the edge for knowledge tasks in this comparison, averaging 56.8 versus 47.3. Inside this category, MMLU-Pro is the benchmark that creates the most daylight between them.

Which is better for coding, Claude 4 Sonnet or Seed 1.6 Flash?

Claude 4 Sonnet has the edge for coding in this comparison, averaging 42.9 versus 27.6. Inside this category, SWE-bench Verified is the benchmark that creates the most daylight between them.

Which is better for math, Claude 4 Sonnet or Seed 1.6 Flash?

Claude 4 Sonnet has the edge for math in this comparison, averaging 76.1 versus 67.1. Inside this category, AIME 2023 is the benchmark that creates the most daylight between them.

Which is better for reasoning, Claude 4 Sonnet or Seed 1.6 Flash?

Claude 4 Sonnet has the edge for reasoning in this comparison, averaging 71.8 versus 66.8. Inside this category, SimpleQA is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, Claude 4 Sonnet or Seed 1.6 Flash?

Claude 4 Sonnet has the edge for agentic tasks in this comparison, averaging 57.9 versus 54.5. Inside this category, OSWorld-Verified is the benchmark that creates the most daylight between them.

Which is better for multimodal and grounded tasks, Claude 4 Sonnet or Seed 1.6 Flash?

Claude 4 Sonnet has the edge for multimodal and grounded tasks in this comparison, averaging 79.7 versus 73.1. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.

Which is better for instruction following, Claude 4 Sonnet or Seed 1.6 Flash?

Claude 4 Sonnet has the edge for instruction following in this comparison, averaging 83 versus 81. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Which is better for multilingual tasks, Claude 4 Sonnet or Seed 1.6 Flash?

Claude 4 Sonnet has the edge for multilingual tasks in this comparison, averaging 82.1 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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