Step 3.5 Flash vs Claude 4.1 Opus

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

Step 3.5 Flash has the cleaner overall profile here, landing at 66 versus 64. It is a real lead, but still close enough that category-level strengths matter more than the headline number.

Step 3.5 Flash's sharpest advantage is in mathematics, where it averages 84.5 against 77.7. The single biggest benchmark swing on the page is MMMU-Pro, 64 to 82. Claude 4.1 Opus does hit back in multimodal & grounded, so the answer changes if that is the part of the workload you care about most.

Step 3.5 Flash gives you the larger context window at 256K, compared with 200K for Claude 4.1 Opus.

Quick Verdict

Pick Step 3.5 Flash if you want the stronger benchmark profile. Claude 4.1 Opus only becomes the better choice if multimodal & grounded is the priority.

Agentic

Step 3.5 Flash

Step 3.5 Flash

60.2

Claude 4.1 Opus

58.7

62
Terminal-Bench 2.0
58
66
BrowseComp
62
54
OSWorld-Verified
57

Coding

Step 3.5 Flash

Step 3.5 Flash

47.1

Claude 4.1 Opus

44

77
HumanEval
68
48
SWE-bench Verified
48
45
LiveCodeBench
40
49
SWE-bench Pro
47

Multimodal & Grounded

Claude 4.1 Opus

Step 3.5 Flash

66.7

Claude 4.1 Opus

80.7

64
MMMU-Pro
82
70
OfficeQA Pro
79

Reasoning

Step 3.5 Flash

Step 3.5 Flash

78.3

Claude 4.1 Opus

72.9

82
SimpleQA
74
82
MuSR
72
83
BBH
81
74
LongBench v2
71
73
MRCRv2
71

Knowledge

Step 3.5 Flash

Step 3.5 Flash

60.8

Claude 4.1 Opus

57.6

84
MMLU
76
83
GPQA
76
81
SuperGPQA
74
79
OpenBookQA
72
76
MMLU-Pro
75
12
HLE
11
71
FrontierScience
68

Instruction Following

Step 3.5 Flash

Step 3.5 Flash

87

Claude 4.1 Opus

83

87
IFEval
83

Multilingual

Step 3.5 Flash

Step 3.5 Flash

82.8

Claude 4.1 Opus

81.8

86
MGSM
85
81
MMLU-ProX
80

Mathematics

Step 3.5 Flash

Step 3.5 Flash

84.5

Claude 4.1 Opus

77.7

85
AIME 2023
76
87
AIME 2024
78
86
AIME 2025
77
81
HMMT Feb 2023
72
83
HMMT Feb 2024
74
82
HMMT Feb 2025
73
84
BRUMO 2025
75
85
MATH-500
81

Frequently Asked Questions

Which is better, Step 3.5 Flash or Claude 4.1 Opus?

Step 3.5 Flash is ahead overall, 66 to 64. The biggest single separator in this matchup is MMMU-Pro, where the scores are 64 and 82.

Which is better for knowledge tasks, Step 3.5 Flash or Claude 4.1 Opus?

Step 3.5 Flash has the edge for knowledge tasks in this comparison, averaging 60.8 versus 57.6. Inside this category, MMLU is the benchmark that creates the most daylight between them.

Which is better for coding, Step 3.5 Flash or Claude 4.1 Opus?

Step 3.5 Flash has the edge for coding in this comparison, averaging 47.1 versus 44. Inside this category, HumanEval is the benchmark that creates the most daylight between them.

Which is better for math, Step 3.5 Flash or Claude 4.1 Opus?

Step 3.5 Flash has the edge for math in this comparison, averaging 84.5 versus 77.7. Inside this category, AIME 2023 is the benchmark that creates the most daylight between them.

Which is better for reasoning, Step 3.5 Flash or Claude 4.1 Opus?

Step 3.5 Flash has the edge for reasoning in this comparison, averaging 78.3 versus 72.9. Inside this category, MuSR is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, Step 3.5 Flash or Claude 4.1 Opus?

Step 3.5 Flash has the edge for agentic tasks in this comparison, averaging 60.2 versus 58.7. 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, Step 3.5 Flash or Claude 4.1 Opus?

Claude 4.1 Opus has the edge for multimodal and grounded tasks in this comparison, averaging 80.7 versus 66.7. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.

Which is better for instruction following, Step 3.5 Flash or Claude 4.1 Opus?

Step 3.5 Flash has the edge for instruction following in this comparison, averaging 87 versus 83. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Which is better for multilingual tasks, Step 3.5 Flash or Claude 4.1 Opus?

Step 3.5 Flash has the edge for multilingual tasks in this comparison, averaging 82.8 versus 81.8. Inside this category, MGSM is the benchmark that creates the most daylight between them.

Last updated: March 12, 2026

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