Claude Haiku 4.5 vs Seed 1.6 Flash

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

Claude Haiku 4.5 is clearly ahead on the aggregate, 62 to 56. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

Claude Haiku 4.5's sharpest advantage is in coding, where it averages 41.7 against 27.6. The single biggest benchmark swing on the page is SWE-bench Verified, 48 to 24.

Claude Haiku 4.5 is also the more expensive model on tokens at $0.80 input / $4.00 output per 1M tokens, versus $0.08 input / $0.30 output per 1M tokens for Seed 1.6 Flash. That is roughly 13.3x on output cost alone. Seed 1.6 Flash is the reasoning model in the pair, while Claude Haiku 4.5 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 Haiku 4.5.

Quick Verdict

Pick Claude Haiku 4.5 if you want the stronger benchmark profile. Seed 1.6 Flash only becomes the better choice if you want the cheaper token bill or you need the larger 256K context window.

Agentic

Claude Haiku 4.5

Claude Haiku 4.5

56.7

Seed 1.6 Flash

54.5

53
Terminal-Bench 2.0
52
62
BrowseComp
62
57
OSWorld-Verified
52

Coding

Claude Haiku 4.5

Claude Haiku 4.5

41.7

Seed 1.6 Flash

27.6

60
HumanEval
59
48
SWE-bench Verified
24
36
LiveCodeBench
25
46
SWE-bench Pro
31

Multimodal & Grounded

Claude Haiku 4.5

Claude Haiku 4.5

78.4

Seed 1.6 Flash

73.1

82
MMMU-Pro
74
74
OfficeQA Pro
72

Reasoning

Claude Haiku 4.5

Claude Haiku 4.5

68.9

Seed 1.6 Flash

66.8

65
SimpleQA
61
63
MuSR
59
81
BBH
75
72
LongBench v2
70
70
MRCRv2
74

Knowledge

Claude Haiku 4.5

Claude Haiku 4.5

53.6

Seed 1.6 Flash

47.3

68
MMLU
65
67
GPQA
64
65
SuperGPQA
62
63
OpenBookQA
60
73
MMLU-Pro
65
11
HLE
3
64
FrontierScience
57

Instruction Following

Claude Haiku 4.5

Claude Haiku 4.5

86

Seed 1.6 Flash

81

86
IFEval
81

Multilingual

Claude Haiku 4.5

Claude Haiku 4.5

80.1

Seed 1.6 Flash

72.8

82
MGSM
76
79
MMLU-ProX
71

Mathematics

Claude Haiku 4.5

Claude Haiku 4.5

73.3

Seed 1.6 Flash

67.1

68
AIME 2023
64
70
AIME 2024
66
69
AIME 2025
65
64
HMMT Feb 2023
60
66
HMMT Feb 2024
62
65
HMMT Feb 2025
61
67
BRUMO 2025
63
81
MATH-500
72

Frequently Asked Questions

Which is better, Claude Haiku 4.5 or Seed 1.6 Flash?

Claude Haiku 4.5 is ahead overall, 62 to 56. The biggest single separator in this matchup is SWE-bench Verified, where the scores are 48 and 24.

Which is better for knowledge tasks, Claude Haiku 4.5 or Seed 1.6 Flash?

Claude Haiku 4.5 has the edge for knowledge tasks in this comparison, averaging 53.6 versus 47.3. Inside this category, MMLU-Pro is the benchmark that creates the most daylight between them.

Which is better for coding, Claude Haiku 4.5 or Seed 1.6 Flash?

Claude Haiku 4.5 has the edge for coding in this comparison, averaging 41.7 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 Haiku 4.5 or Seed 1.6 Flash?

Claude Haiku 4.5 has the edge for math in this comparison, averaging 73.3 versus 67.1. Inside this category, MATH-500 is the benchmark that creates the most daylight between them.

Which is better for reasoning, Claude Haiku 4.5 or Seed 1.6 Flash?

Claude Haiku 4.5 has the edge for reasoning in this comparison, averaging 68.9 versus 66.8. Inside this category, BBH is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, Claude Haiku 4.5 or Seed 1.6 Flash?

Claude Haiku 4.5 has the edge for agentic tasks in this comparison, averaging 56.7 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 Haiku 4.5 or Seed 1.6 Flash?

Claude Haiku 4.5 has the edge for multimodal and grounded tasks in this comparison, averaging 78.4 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 Haiku 4.5 or Seed 1.6 Flash?

Claude Haiku 4.5 has the edge for instruction following in this comparison, averaging 86 versus 81. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Which is better for multilingual tasks, Claude Haiku 4.5 or Seed 1.6 Flash?

Claude Haiku 4.5 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

Weekly LLM Benchmark Digest

Get notified when new models drop, benchmark scores change, or the leaderboard shifts. One email per week.

Free. No spam. Unsubscribe anytime. We only store derived location metadata for consent routing.