Noometry

Model comparison

Gemini 3.1 Pro Preview vs Gemini 3.5 Flash

Gemini 3.1 Pro Preview is the stronger model overall, scoring 56.7 to 54.2 on the Noometry Index.

Last verified . 53 shared benchmarks.

Gemini 3.1 Pro Preview Google

56.7

Rank #23 Confirmed

Gemini 3.5 Flash Google

54.2

Rank #32 Confirmed

Summary

  • They share 53 benchmarks with published results for both. Gemini 3.1 Pro Preview scores higher in 7 categories and Gemini 3.5 Flash in 3 categories; 7 gaps are clear of the uncertainty.
  • The widest gap is in agentic & tool use, where Gemini 3.1 Pro Preview leads 37.7 to 24.7.
  • The biggest single-benchmark swing is DeepSWE: 11.7% for Gemini 3.1 Pro Preview and 37.4% for Gemini 3.5 Flash.
  • Gemini 3.5 Flash is cheaper at $1.50 / $9 per million input/output tokens, against $2 / $12 for Gemini 3.1 Pro Preview.

Side by side

Gemini 3.1 Pro PreviewGemini 3.5 Flash
ProviderGoogleGoogle
Noometry Index56.754.2
Released2026-02-192026-05-19
WeightsProprietaryProprietary
Context window1.05M1.05M
Max output66K66K
Input $ / M tokens$2$1.50
Output $ / M tokens$12$9
Results tracked7154

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Category by category

Coding Gemini 3.5 Flash leads

Gemini 3.1 Pro Preview: 42.5 (#99), Gemini 3.5 Flash: 49.4 (#49)

BenchmarkGemini 3.1 Pro PreviewGemini 3.5 Flash
SWE-bench Verified75.6%79.3%
DeepSWE11.7%37.4%
LMArena WebDev14471499
SciCode58.9%53.1%
WeirdML72.1%62.6%
LMArena Coding14841492
ALE-Bench1,161911.02
GSO22.6%—
MirrorCode8.9%—
AlgoTune2.02—

Agentic & Tool Use Gemini 3.1 Pro Preview leads

Gemini 3.1 Pro Preview: 37.7 (#34), Gemini 3.5 Flash: 24.7 (#114)

BenchmarkGemini 3.1 Pro PreviewGemini 3.5 Flash
APEX-Agents35.3%27.5%
GBAEval0.8%6.7%
GDP.pdf17%14%
Vending-Bench 23,7745,396
Terminal-Bench80.2%—
τ²-bench Banking26%—
DeepResearch Bench47.8%—
PostTrainBench22%—
BALROG57%—
ExploitBench26.1%—
LMArena Search1211—
METR Time Horizons77%—

Reasoning Gemini 3.1 Pro Preview leads

Gemini 3.1 Pro Preview: 71.7 (#12), Gemini 3.5 Flash: 62.8 (#18)

BenchmarkGemini 3.1 Pro PreviewGemini 3.5 Flash
ARC-AGI-277.1%72.1%
SimpleBench79.6%76.7%
NYT Connections (extended)97.4%92.6%
ARC-AGI-198%92.5%
CritPt17.7%13.1%
Chess Puzzles55%50%
EnigmaEval36.8%25.4%
EBR-Bench14.3%4.8%
LMArena Hard Prompts14851488
Mystery Game Puzzles34%32%
DTBench97.1%94.7%
LMCA53.8%47.1%
Epoch Capabilities Index154.77154.46
ForecastBench5959
Thematic Generalization79.4%—
Surface Evolver Bench—58.1%

Math Gemini 3.1 Pro Preview leads

Gemini 3.1 Pro Preview: 62.1 (#34), Gemini 3.5 Flash: 60.7 (#36)

BenchmarkGemini 3.1 Pro PreviewGemini 3.5 Flash
FrontierMath (Tiers 1-3)59.6%62.8%
FrontierMath Tier 426.8%26.8%
MathArena Final-Answer Competitions86.5%76.3%
OTIS Mock AIME 2024-202595.6%95.6%
ProofBench26%31%
LMArena Math14851504
FrontierMath (Feb 2025 set)36.9%39%
FrontierMath Tier 4 (v1)16.7%14.6%

Knowledge Gemini 3.1 Pro Preview leads

Gemini 3.1 Pro Preview: 71.8 (#3), Gemini 3.5 Flash: 66.3 (#11)

BenchmarkGemini 3.1 Pro PreviewGemini 3.5 Flash
GPQA Diamond94.4%92.8%
SimpleQA Verified73.5%66.2%
LMArena Expert14851495
Humanity's Last Exam46.4%—
Vectara Hallucination Rate10.4%—

Multimodal Gemini 3.5 Flash leads

Gemini 3.1 Pro Preview: 37.9 (#69), Gemini 3.5 Flash: 45.7 (#15)

BenchmarkGemini 3.1 Pro PreviewGemini 3.5 Flash
LMArena Vision12961310
Blueprint-Bench 226.5%33.6%
LMArena Document14441463
Furniture Assembly26.7%—

Multilingual Too close to call

Gemini 3.1 Pro Preview: 57.0 (#12), Gemini 3.5 Flash: 57.0 (#13)

BenchmarkGemini 3.1 Pro PreviewGemini 3.5 Flash
LMArena Non-English14771476
LMArena Chinese15291526
LMArena French14871490
LMArena German14911492
LMArena Japanese14931486
LMArena Korean14551451
LMArena Russian14981493
LMArena Spanish14791480

Instruction Following Too close to call

Gemini 3.1 Pro Preview: 77.0 (#32), Gemini 3.5 Flash: 77.0 (#30)

BenchmarkGemini 3.1 Pro PreviewGemini 3.5 Flash
LMArena Instruction Following14661467

Long Context Gemini 3.1 Pro Preview leads

Gemini 3.1 Pro Preview: 47.4 (#18), Gemini 3.5 Flash: 45.4 (#38)

BenchmarkGemini 3.1 Pro PreviewGemini 3.5 Flash
LMArena Longer Query14831482
CL-bench20.8%—
CL-bench Life16.9%—

Writing & Preference Too close to call

Gemini 3.1 Pro Preview: 66.1 (#37), Gemini 3.5 Flash: 65.5 (#47)

BenchmarkGemini 3.1 Pro PreviewGemini 3.5 Flash
LMArena Text14811482
LMArena Creative Writing14821470
EQ-Bench 411421087
LMArena Multi-Turn14881481
EQ-Bench Creative Writing1491—

Frequently asked questions

Is Gemini 3.1 Pro Preview better than Gemini 3.5 Flash?

Gemini 3.1 Pro Preview is the stronger model overall, scoring 56.7 to 54.2 on the Noometry Index.

Which is cheaper, Gemini 3.1 Pro Preview or Gemini 3.5 Flash?

Gemini 3.5 Flash is cheaper. It lists at $1.50 per million input tokens and $9 per million output tokens; Gemini 3.1 Pro Preview lists at $2 and $12.

Is Gemini 3.1 Pro Preview or Gemini 3.5 Flash better for coding?

Gemini 3.5 Flash scores higher on coding benchmarks: 49.4 versus 42.5 in the Noometry coding category.

Which has the bigger context window?

Both accept 1.05M tokens.

How many benchmarks do Gemini 3.1 Pro Preview and Gemini 3.5 Flash share?

53 benchmarks have published results for both models. Gemini 3.1 Pro Preview has 71 scored results on Noometry and Gemini 3.5 Flash has 54.

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