Model comparison

Gemini 2.5 Flash vs o1

o1 is the stronger model overall, scoring 40.9 to 39.3 on the Noometry Index. Gemini 2.5 Flash costs 31× less per token, which makes it the better buy when o1's lead doesn't matter for your workload.

Last verified . 35 shared benchmarks.

Gemini 2.5 Flash Google

39.3

Rank #170 Confirmed

o1 OpenAI

40.9

Rank #143 Confirmed

Summary

  • They share 35 benchmarks with published results for both. Gemini 2.5 Flash scores higher in 5 categories and o1 in 5 categories; 9 gaps are clear of the uncertainty.
  • The widest gap is in coding, where o1 leads 46.1 to 35.8.
  • The biggest single-benchmark swing is VPCT: 46.2% for Gemini 2.5 Flash and 37% for o1.
  • Gemini 2.5 Flash is cheaper at $0.30 / $2.50 per million input/output tokens, against $15 / $60 for o1.
  • Gemini 2.5 Flash accepts more context: 1.05M tokens versus 200K.

Side by side

Gemini 2.5 Flash and o1 specifications
Gemini 2.5 Flasho1
ProviderGoogleOpenAI
Noometry Index39.340.9
Released2025-04-172024-09-12
WeightsProprietaryProprietary
Context window1.05M200K
Max output66K100K
Input $ / M tokens$0.30$15
Output $ / M tokens$2.50$60
Results tracked5452

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Category by category

Coding o1 leads

Gemini 2.5 Flash: 35.8 (#220), o1: 46.1 (#70)

Coding benchmarks
BenchmarkGemini 2.5 Flasho1
Aider Polyglot55.1%61.7%
WeirdML41.9%47.6%
LMArena Coding14241367
SWE-bench Verified (bash only)28.7%—
LiveBench Coding—69.7%
CadEval—56%
ALE-Bench661.88—
HumanEval+—89%
MBPP+—80.2%

Agentic & Tool Use Gemini 2.5 Flash leads

Gemini 2.5 Flash: 30.8 (#74), o1: 24.6 (#117)

Agentic & Tool Use benchmarks
BenchmarkGemini 2.5 Flasho1
Terminal-Bench17.1%—
Berkeley Function Calling Leaderboard56.2%—
TheAgentCompany41.1%—
Cybench—10%
BALROG33.5%—
METR Time Horizons—51.1%
Vending-Bench 2548.84—

Reasoning o1 leads

Gemini 2.5 Flash: 18.1 (#286), o1: 27.9 (#111)

Reasoning benchmarks
BenchmarkGemini 2.5 Flasho1
SimpleBench41.2%41.7%
ARC-AGI-133.3%30.7%
EnigmaEval2.7%5.7%
LMArena Hard Prompts14221371
DTBench76.5%74.7%
LMCA27.5%22.3%
Epoch Capabilities Index143.03141.91
ARC-AGI-22.5%—
Kagi LLM Benchmark56.8%—
CritPt1.1%—
Chess Puzzles—15%
LiveBench Reasoning—91.6%
LiveBench Data Analysis—65.5%
ForecastBench60.6—
LiveBench—75.7%

Math Gemini 2.5 Flash leads

Gemini 2.5 Flash: 39.9 (#98), o1: 36.1 (#175)

Math benchmarks
BenchmarkGemini 2.5 Flasho1
OTIS Mock AIME 2024-202573.1%73.3%
LMArena Math14151388
FrontierMath (Feb 2025 set)4.8%9.3%
FrontierMath (Tiers 1-3)—14.7%
Omni-MATH38.5%—
LiveBench Math—80.3%
MATH Level 5—94.7%
FrontierMath Tier 4 (v1)4.2%—

Knowledge o1 leads

Gemini 2.5 Flash: 36.4 (#168), o1: 41.5 (#110)

Knowledge benchmarks
BenchmarkGemini 2.5 Flasho1
Humanity's Last Exam12.1%8%
Confabulations16.8%11.7%
LMArena Expert14261361
GPQA Diamond—76.8%
SimpleQA Verified—41.1%
MMLU-Pro63.9%—
Vectara Hallucination Rate7.8%—
GPQA (HELM)39%—

Multimodal Gemini 2.5 Flash leads

Gemini 2.5 Flash: 41.8 (#32), o1: 34.2 (#93)

Multimodal benchmarks
BenchmarkGemini 2.5 Flasho1
LMArena Vision12531168
GeoBench76%80%
VPCT46.2%37%
SpatialViz-Bench36.9%41.4%

Multilingual Gemini 2.5 Flash leads

Gemini 2.5 Flash: 52.3 (#88), o1: 48.6 (#142)

Multilingual benchmarks
BenchmarkGemini 2.5 Flasho1
LMArena Non-English14091358
LMArena Chinese14501394
LMArena French14331344
LMArena German14181337
LMArena Japanese14051346
LMArena Korean13851396
LMArena Russian14151356
LMArena Spanish14211345

Instruction Following Too close to call

Gemini 2.5 Flash: 75.7 (#54), o1: 74.8 (#86)

Instruction Following benchmarks
BenchmarkGemini 2.5 Flasho1
LMArena Instruction Following14051367
LiveBench Instruction Following—81.5%
IFEval89.8%—

Long Context o1 leads

Gemini 2.5 Flash: 47.5 (#17), o1: 50.3 (#9)

Long Context benchmarks
BenchmarkGemini 2.5 Flasho1
Fiction.LiveBench77.8%83.3%
LMArena Longer Query14191378

Writing & Preference o1 leads

Gemini 2.5 Flash: 53.8 (#157), o1: 55.6 (#144)

Writing & Preference benchmarks
BenchmarkGemini 2.5 Flasho1
LMArena Text14171366
LMArena Creative Writing14001348
Short-Story Creative Writing76.5%70.2%
LMArena Multi-Turn14081369
EQ-Bench Creative Writing1137—
WildBench81.7%—
LiveBench Language—65.4%

Frequently asked questions

Is Gemini 2.5 Flash better than o1?

o1 is the stronger model overall, scoring 40.9 to 39.3 on the Noometry Index. Gemini 2.5 Flash costs 31× less per token, which makes it the better buy when o1's lead doesn't matter for your workload.

Which is cheaper, Gemini 2.5 Flash or o1?

Gemini 2.5 Flash is cheaper. It lists at $0.30 per million input tokens and $2.50 per million output tokens; o1 lists at $15 and $60.

Is Gemini 2.5 Flash or o1 better for coding?

o1 scores higher on coding benchmarks: 46.1 versus 35.8 in the Noometry coding category.

Which has the bigger context window?

Gemini 2.5 Flash does, with 1.05M tokens against 200K.

How many benchmarks do Gemini 2.5 Flash and o1 share?

35 benchmarks have published results for both models. Gemini 2.5 Flash has 54 scored results on Noometry and o1 has 52.

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