Gemini 3.1 Pro vs Mercury 2

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

Gemini 3.1 Pro is clearly ahead on the aggregate, 84 to 65. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

Gemini 3.1 Pro's sharpest advantage is in coding, where it averages 71.9 against 41.1. The single biggest benchmark swing on the page is LiveCodeBench, 71 to 38.

Gemini 3.1 Pro is also the more expensive model on tokens at $1.25 input / $5.00 output per 1M tokens, versus $0.25 input / $0.75 output per 1M tokens for Mercury 2. That is roughly 6.7x on output cost alone. Mercury 2 is the reasoning model in the pair, while Gemini 3.1 Pro 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. Gemini 3.1 Pro gives you the larger context window at 1M, compared with 128K for Mercury 2.

Quick Verdict

Pick Gemini 3.1 Pro if you want the stronger benchmark profile. Mercury 2 only becomes the better choice if you want the cheaper token bill or you want the stronger reasoning-first profile.

Agentic

Gemini 3.1 Pro

Gemini 3.1 Pro

76.1

Mercury 2

63.7

77
Terminal-Bench 2.0
63
86
BrowseComp
67
68
OSWorld-Verified
62

Coding

Gemini 3.1 Pro

Gemini 3.1 Pro

71.9

Mercury 2

41.1

91
HumanEval
75
75
SWE-bench Verified
46
71
LiveCodeBench
38
72
SWE-bench Pro
43

Multimodal & Grounded

Gemini 3.1 Pro

Gemini 3.1 Pro

95

Mercury 2

68.3

95
MMMU-Pro
66
95
OfficeQA Pro
71

Reasoning

Gemini 3.1 Pro

Gemini 3.1 Pro

92.7

Mercury 2

80.1

95
SimpleQA
82
93
MuSR
82
92
BBH
87
93
LongBench v2
77
90
MRCRv2
76

Knowledge

Gemini 3.1 Pro

Gemini 3.1 Pro

79.4

Mercury 2

57.2

99
MMLU
78
97
GPQA
78
95
SuperGPQA
76
93
OpenBookQA
74
92
MMLU-Pro
72
40
HLE
9
88
FrontierScience
69

Instruction Following

Gemini 3.1 Pro

Gemini 3.1 Pro

95

Mercury 2

84

95
IFEval
84

Multilingual

Gemini 3.1 Pro

Gemini 3.1 Pro

94.1

Mercury 2

79.7

96
MGSM
81
93
MMLU-ProX
79

Mathematics

Gemini 3.1 Pro

Gemini 3.1 Pro

96.8

Mercury 2

80.9

99
AIME 2023
81
99
AIME 2024
83
98
AIME 2025
82
95
HMMT Feb 2023
77
97
HMMT Feb 2024
79
96
HMMT Feb 2025
78
96
BRUMO 2025
80
97
MATH-500
82

Frequently Asked Questions

Which is better, Gemini 3.1 Pro or Mercury 2?

Gemini 3.1 Pro is ahead overall, 84 to 65. The biggest single separator in this matchup is LiveCodeBench, where the scores are 71 and 38.

Which is better for knowledge tasks, Gemini 3.1 Pro or Mercury 2?

Gemini 3.1 Pro has the edge for knowledge tasks in this comparison, averaging 79.4 versus 57.2. Inside this category, HLE is the benchmark that creates the most daylight between them.

Which is better for coding, Gemini 3.1 Pro or Mercury 2?

Gemini 3.1 Pro has the edge for coding in this comparison, averaging 71.9 versus 41.1. Inside this category, LiveCodeBench is the benchmark that creates the most daylight between them.

Which is better for math, Gemini 3.1 Pro or Mercury 2?

Gemini 3.1 Pro has the edge for math in this comparison, averaging 96.8 versus 80.9. Inside this category, AIME 2023 is the benchmark that creates the most daylight between them.

Which is better for reasoning, Gemini 3.1 Pro or Mercury 2?

Gemini 3.1 Pro has the edge for reasoning in this comparison, averaging 92.7 versus 80.1. Inside this category, LongBench v2 is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, Gemini 3.1 Pro or Mercury 2?

Gemini 3.1 Pro has the edge for agentic tasks in this comparison, averaging 76.1 versus 63.7. Inside this category, BrowseComp is the benchmark that creates the most daylight between them.

Which is better for multimodal and grounded tasks, Gemini 3.1 Pro or Mercury 2?

Gemini 3.1 Pro has the edge for multimodal and grounded tasks in this comparison, averaging 95 versus 68.3. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.

Which is better for instruction following, Gemini 3.1 Pro or Mercury 2?

Gemini 3.1 Pro has the edge for instruction following in this comparison, averaging 95 versus 84. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Which is better for multilingual tasks, Gemini 3.1 Pro or Mercury 2?

Gemini 3.1 Pro has the edge for multilingual tasks in this comparison, averaging 94.1 versus 79.7. Inside this category, MGSM is the benchmark that creates the most daylight between them.

Last updated: March 12, 2026

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