Noometry

Model comparison

Gemini 2.5 Flash vs Gemini 3.5 Flash

Gemini 3.5 Flash is the stronger model overall, scoring 54.2 to 39.3 on the Noometry Index. Gemini 2.5 Flash costs 4.0× less per token, which makes it the better buy when Gemini 3.5 Flash's lead doesn't matter for your workload.

Last verified . 33 shared benchmarks.

Gemini 2.5 Flash Google

39.3

Rank #170 Confirmed

Gemini 3.5 Flash Google

54.2

Rank #32 Confirmed

Summary

  • They share 33 benchmarks with published results for both. Gemini 2.5 Flash scores higher in 2 categories and Gemini 3.5 Flash in 8 categories; 10 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where Gemini 3.5 Flash leads 62.8 to 18.1.
  • The biggest single-benchmark swing is ARC-AGI-2: 2.5% for Gemini 2.5 Flash and 72.1% for Gemini 3.5 Flash.
  • Gemini 2.5 Flash is cheaper at $0.30 / $2.50 per million input/output tokens, against $1.50 / $9 for Gemini 3.5 Flash.

Side by side

Gemini 2.5 FlashGemini 3.5 Flash
ProviderGoogleGoogle
Noometry Index39.354.2
Released2025-04-172026-05-19
WeightsProprietaryProprietary
Context window1.05M1.05M
Max output66K66K
Input $ / M tokens$0.30$1.50
Output $ / M tokens$2.50$9
Results tracked5454

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Category by category

Coding Gemini 3.5 Flash leads

Gemini 2.5 Flash: 35.8 (#220), Gemini 3.5 Flash: 49.4 (#49)

BenchmarkGemini 2.5 FlashGemini 3.5 Flash
WeirdML41.9%62.6%
LMArena Coding14241492
ALE-Bench661.88911.02
SWE-bench Verified—79.3%
DeepSWE—37.4%
SWE-bench Verified (bash only)28.7%—
Aider Polyglot55.1%—
LMArena WebDev—1499
SciCode—53.1%

Agentic & Tool Use Gemini 2.5 Flash leads

Gemini 2.5 Flash: 30.8 (#74), Gemini 3.5 Flash: 24.7 (#114)

BenchmarkGemini 2.5 FlashGemini 3.5 Flash
Vending-Bench 2548.845,396
Terminal-Bench17.1%—
APEX-Agents—27.5%
Berkeley Function Calling Leaderboard56.2%—
TheAgentCompany41.1%—
BALROG33.5%—
GBAEval—6.7%
GDP.pdf—14%

Reasoning Gemini 3.5 Flash leads

Gemini 2.5 Flash: 18.1 (#286), Gemini 3.5 Flash: 62.8 (#18)

BenchmarkGemini 2.5 FlashGemini 3.5 Flash
ARC-AGI-22.5%72.1%
SimpleBench41.2%76.7%
ARC-AGI-133.3%92.5%
CritPt1.1%13.1%
EnigmaEval2.7%25.4%
LMArena Hard Prompts14221488
DTBench76.5%94.7%
LMCA27.5%47.1%
Epoch Capabilities Index143.03154.46
ForecastBench60.659
Kagi LLM Benchmark56.8%—
NYT Connections (extended)—92.6%
Chess Puzzles—50%
EBR-Bench—4.8%
Mystery Game Puzzles—32%
Surface Evolver Bench—58.1%

Math Gemini 3.5 Flash leads

Gemini 2.5 Flash: 39.9 (#98), Gemini 3.5 Flash: 60.7 (#36)

BenchmarkGemini 2.5 FlashGemini 3.5 Flash
OTIS Mock AIME 2024-202573.1%95.6%
LMArena Math14151504
FrontierMath (Feb 2025 set)4.8%39%
FrontierMath Tier 4 (v1)4.2%14.6%
FrontierMath (Tiers 1-3)—62.8%
FrontierMath Tier 4—26.8%
MathArena Final-Answer Competitions—76.3%
ProofBench—31%
Omni-MATH38.5%—

Knowledge Gemini 3.5 Flash leads

Gemini 2.5 Flash: 36.4 (#168), Gemini 3.5 Flash: 66.3 (#11)

BenchmarkGemini 2.5 FlashGemini 3.5 Flash
LMArena Expert14261495
GPQA Diamond—92.8%
Humanity's Last Exam12.1%—
SimpleQA Verified—66.2%
MMLU-Pro63.9%—
Confabulations16.8%—
Vectara Hallucination Rate7.8%—
GPQA (HELM)39%—

Multimodal Gemini 3.5 Flash leads

Gemini 2.5 Flash: 41.8 (#32), Gemini 3.5 Flash: 45.7 (#15)

BenchmarkGemini 2.5 FlashGemini 3.5 Flash
LMArena Vision12531310
GeoBench76%—
VPCT46.2%—
Blueprint-Bench 2—33.6%
LMArena Document—1463
SpatialViz-Bench36.9%—

Multilingual Gemini 3.5 Flash leads

Gemini 2.5 Flash: 52.3 (#88), Gemini 3.5 Flash: 57.0 (#13)

BenchmarkGemini 2.5 FlashGemini 3.5 Flash
LMArena Non-English14091476
LMArena Chinese14501526
LMArena French14331490
LMArena German14181492
LMArena Japanese14051486
LMArena Korean13851451
LMArena Russian14151493
LMArena Spanish14211480

Instruction Following Gemini 3.5 Flash leads

Gemini 2.5 Flash: 75.7 (#54), Gemini 3.5 Flash: 77.0 (#30)

BenchmarkGemini 2.5 FlashGemini 3.5 Flash
LMArena Instruction Following14051467
IFEval89.8%—

Long Context Gemini 2.5 Flash leads

Gemini 2.5 Flash: 47.5 (#17), Gemini 3.5 Flash: 45.4 (#38)

BenchmarkGemini 2.5 FlashGemini 3.5 Flash
LMArena Longer Query14191482
Fiction.LiveBench77.8%—

Writing & Preference Gemini 3.5 Flash leads

Gemini 2.5 Flash: 53.8 (#157), Gemini 3.5 Flash: 65.5 (#47)

BenchmarkGemini 2.5 FlashGemini 3.5 Flash
LMArena Text14171482
LMArena Creative Writing14001470
LMArena Multi-Turn14081481
Short-Story Creative Writing76.5%—
EQ-Bench Creative Writing1137—
WildBench81.7%—
EQ-Bench 4—1087

Frequently asked questions

Is Gemini 2.5 Flash better than Gemini 3.5 Flash?

Gemini 3.5 Flash is the stronger model overall, scoring 54.2 to 39.3 on the Noometry Index. Gemini 2.5 Flash costs 4.0× less per token, which makes it the better buy when Gemini 3.5 Flash's lead doesn't matter for your workload.

Which is cheaper, Gemini 2.5 Flash or Gemini 3.5 Flash?

Gemini 2.5 Flash is cheaper. It lists at $0.30 per million input tokens and $2.50 per million output tokens; Gemini 3.5 Flash lists at $1.50 and $9.

Is Gemini 2.5 Flash or Gemini 3.5 Flash better for coding?

Gemini 3.5 Flash scores higher on coding benchmarks: 49.4 versus 35.8 in the Noometry coding category.

Which has the bigger context window?

Both accept 1.05M tokens.

How many benchmarks do Gemini 2.5 Flash and Gemini 3.5 Flash share?

33 benchmarks have published results for both models. Gemini 2.5 Flash has 54 scored results on Noometry and Gemini 3.5 Flash has 54.

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