Step 3.5 Flash vs Gemini 3 Flash

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

Step 3.5 Flash is clearly ahead on the aggregate, 66 to 62. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

Step 3.5 Flash's sharpest advantage is in mathematics, where it averages 84.5 against 74. The single biggest benchmark swing on the page is MuSR, 82 to 65. Gemini 3 Flash does hit back in multimodal & grounded, so the answer changes if that is the part of the workload you care about most.

Gemini 3 Flash is also the more expensive model on tokens at $0.50 input / $3.00 output per 1M tokens, versus $0.10 input / $0.30 output per 1M tokens for Step 3.5 Flash. That is roughly 10.0x on output cost alone. Gemini 3 Flash gives you the larger context window at 1M, compared with 256K for Step 3.5 Flash.

Quick Verdict

Pick Step 3.5 Flash if you want the stronger benchmark profile. Gemini 3 Flash only becomes the better choice if multimodal & grounded is the priority or you need the larger 1M context window.

Agentic

Step 3.5 Flash

Step 3.5 Flash

60.2

Gemini 3 Flash

57.5

62
Terminal-Bench 2.0
56
66
BrowseComp
66
54
OSWorld-Verified
53

Coding

Step 3.5 Flash

Step 3.5 Flash

47.1

Gemini 3 Flash

40.4

77
HumanEval
62
48
SWE-bench Verified
44
45
LiveCodeBench
36
49
SWE-bench Pro
44

Multimodal & Grounded

Gemini 3 Flash

Step 3.5 Flash

66.7

Gemini 3 Flash

79.6

64
MMMU-Pro
80
70
OfficeQA Pro
79

Reasoning

Step 3.5 Flash

Step 3.5 Flash

78.3

Gemini 3 Flash

72

82
SimpleQA
67
82
MuSR
65
83
BBH
84
74
LongBench v2
75
73
MRCRv2
76

Knowledge

Step 3.5 Flash

Step 3.5 Flash

60.8

Gemini 3 Flash

52.9

84
MMLU
70
83
GPQA
69
81
SuperGPQA
67
79
OpenBookQA
65
76
MMLU-Pro
72
12
HLE
6
71
FrontierScience
65

Instruction Following

Step 3.5 Flash

Step 3.5 Flash

87

Gemini 3 Flash

85

87
IFEval
85

Multilingual

Step 3.5 Flash

Step 3.5 Flash

82.8

Gemini 3 Flash

80.5

86
MGSM
85
81
MMLU-ProX
78

Mathematics

Step 3.5 Flash

Step 3.5 Flash

84.5

Gemini 3 Flash

74

85
AIME 2023
70
87
AIME 2024
72
86
AIME 2025
71
81
HMMT Feb 2023
66
83
HMMT Feb 2024
68
82
HMMT Feb 2025
67
84
BRUMO 2025
69
85
MATH-500
80

Frequently Asked Questions

Which is better, Step 3.5 Flash or Gemini 3 Flash?

Step 3.5 Flash is ahead overall, 66 to 62. The biggest single separator in this matchup is MuSR, where the scores are 82 and 65.

Which is better for knowledge tasks, Step 3.5 Flash or Gemini 3 Flash?

Step 3.5 Flash has the edge for knowledge tasks in this comparison, averaging 60.8 versus 52.9. Inside this category, MMLU is the benchmark that creates the most daylight between them.

Which is better for coding, Step 3.5 Flash or Gemini 3 Flash?

Step 3.5 Flash has the edge for coding in this comparison, averaging 47.1 versus 40.4. Inside this category, HumanEval is the benchmark that creates the most daylight between them.

Which is better for math, Step 3.5 Flash or Gemini 3 Flash?

Step 3.5 Flash has the edge for math in this comparison, averaging 84.5 versus 74. 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 Gemini 3 Flash?

Step 3.5 Flash has the edge for reasoning in this comparison, averaging 78.3 versus 72. 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 Gemini 3 Flash?

Step 3.5 Flash has the edge for agentic tasks in this comparison, averaging 60.2 versus 57.5. 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, Step 3.5 Flash or Gemini 3 Flash?

Gemini 3 Flash has the edge for multimodal and grounded tasks in this comparison, averaging 79.6 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 Gemini 3 Flash?

Step 3.5 Flash has the edge for instruction following in this comparison, averaging 87 versus 85. 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 Gemini 3 Flash?

Step 3.5 Flash has the edge for multilingual tasks in this comparison, averaging 82.8 versus 80.5. Inside this category, MMLU-ProX is the benchmark that creates the most daylight between them.

Last updated: March 12, 2026

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