Step 3.5 Flash vs Gemini 3.1 Flash-Lite

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 53. 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 coding, where it averages 47.1 against 24.7. The single biggest benchmark swing on the page is SWE-bench Verified, 48 to 22. Gemini 3.1 Flash-Lite does hit back in multimodal & grounded, so the answer changes if that is the part of the workload you care about most.

Gemini 3.1 Flash-Lite is also the more expensive model on tokens at $0.10 input / $0.40 output per 1M tokens, versus $0.10 input / $0.30 output per 1M tokens for Step 3.5 Flash. Gemini 3.1 Flash-Lite 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 3.1 Flash-Lite 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 3.1 Flash-Lite

49.2

62
Terminal-Bench 2.0
47
66
BrowseComp
60
54
OSWorld-Verified
44

Coding

Step 3.5 Flash

Step 3.5 Flash

47.1

Gemini 3.1 Flash-Lite

24.7

77
HumanEval
55
48
SWE-bench Verified
22
45
LiveCodeBench
21
49
SWE-bench Pro
29

Multimodal & Grounded

Gemini 3.1 Flash-Lite

Step 3.5 Flash

66.7

Gemini 3.1 Flash-Lite

73.1

64
MMMU-Pro
74
70
OfficeQA Pro
72

Reasoning

Step 3.5 Flash

Step 3.5 Flash

78.3

Gemini 3.1 Flash-Lite

65.8

82
SimpleQA
60
82
MuSR
58
83
BBH
74
74
LongBench v2
69
73
MRCRv2
73

Knowledge

Step 3.5 Flash

Step 3.5 Flash

60.8

Gemini 3.1 Flash-Lite

45.3

84
MMLU
63
83
GPQA
62
81
SuperGPQA
60
79
OpenBookQA
58
76
MMLU-Pro
63
12
HLE
1
71
FrontierScience
55

Instruction Following

Step 3.5 Flash

Step 3.5 Flash

87

Gemini 3.1 Flash-Lite

79

87
IFEval
79

Multilingual

Step 3.5 Flash

Step 3.5 Flash

82.8

Gemini 3.1 Flash-Lite

69.8

86
MGSM
73
81
MMLU-ProX
68

Mathematics

Step 3.5 Flash

Step 3.5 Flash

84.5

Gemini 3.1 Flash-Lite

66.1

85
AIME 2023
63
87
AIME 2024
65
86
AIME 2025
64
81
HMMT Feb 2023
59
83
HMMT Feb 2024
61
82
HMMT Feb 2025
60
84
BRUMO 2025
62
85
MATH-500
71

Frequently Asked Questions

Which is better, Step 3.5 Flash or Gemini 3.1 Flash-Lite?

Step 3.5 Flash is ahead overall, 66 to 53. The biggest single separator in this matchup is SWE-bench Verified, where the scores are 48 and 22.

Which is better for knowledge tasks, Step 3.5 Flash or Gemini 3.1 Flash-Lite?

Step 3.5 Flash has the edge for knowledge tasks in this comparison, averaging 60.8 versus 45.3. 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 3.1 Flash-Lite?

Step 3.5 Flash has the edge for coding in this comparison, averaging 47.1 versus 24.7. Inside this category, SWE-bench Verified is the benchmark that creates the most daylight between them.

Which is better for math, Step 3.5 Flash or Gemini 3.1 Flash-Lite?

Step 3.5 Flash has the edge for math in this comparison, averaging 84.5 versus 66.1. 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 3.1 Flash-Lite?

Step 3.5 Flash has the edge for reasoning in this comparison, averaging 78.3 versus 65.8. 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 3.1 Flash-Lite?

Step 3.5 Flash has the edge for agentic tasks in this comparison, averaging 60.2 versus 49.2. 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 3.1 Flash-Lite?

Gemini 3.1 Flash-Lite has the edge for multimodal and grounded tasks in this comparison, averaging 73.1 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 3.1 Flash-Lite?

Step 3.5 Flash has the edge for instruction following in this comparison, averaging 87 versus 79. 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 3.1 Flash-Lite?

Step 3.5 Flash has the edge for multilingual tasks in this comparison, averaging 82.8 versus 69.8. Inside this category, MGSM is the benchmark that creates the most daylight between them.

Last updated: March 12, 2026

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