Model comparison

Gemini 2.5 Flash vs GPT-5

GPT-5 is the stronger model overall, scoring 50.9 to 39.3 on the Noometry Index. Gemini 2.5 Flash costs 4.0× less per token, which makes it the better buy when GPT-5's lead doesn't matter for your workload.

Last verified . 50 shared benchmarks.

Gemini 2.5 Flash Google

39.3

Rank #170 Confirmed

GPT-5 OpenAI

50.9

Rank #45 Confirmed

Summary

  • They share 50 benchmarks with published results for both. Gemini 2.5 Flash scores higher in 2 categories and GPT-5 in 8 categories; 9 gaps are clear of the uncertainty.
  • The widest gap is in long context, where GPT-5 leads 69.5 to 47.5.
  • The biggest single-benchmark swing is GPQA (HELM): 39% for Gemini 2.5 Flash and 79.2% for GPT-5.
  • Gemini 2.5 Flash is cheaper at $0.30 / $2.50 per million input/output tokens, against $1.25 / $10 for GPT-5.
  • Gemini 2.5 Flash accepts more context: 1.05M tokens versus 400K.

Side by side

Gemini 2.5 Flash and GPT-5 specifications
Gemini 2.5 FlashGPT-5
ProviderGoogleOpenAI
Noometry Index39.350.9
Released2025-04-172025-08-07
WeightsProprietaryProprietary
Context window1.05M400K
Max output66K128K
Input $ / M tokens$0.30$1.25
Output $ / M tokens$2.50$10
Results tracked5469

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Category by category

Coding GPT-5 leads

Gemini 2.5 Flash: 35.8 (#220), GPT-5: 50.3 (#47)

Coding benchmarks
BenchmarkGemini 2.5 FlashGPT-5
SWE-bench Verified (bash only)28.7%65%
Aider Polyglot55.1%88%
WeirdML41.9%60.7%
LMArena Coding14241436
ALE-Bench661.881,162
SWE-bench Verified—73.6%
LMArena WebDev—1418
SciCode—42.9%
GSO—6.9%
AlgoTune—1.67

Agentic & Tool Use GPT-5 leads

Gemini 2.5 Flash: 30.8 (#74), GPT-5: 33.1 (#56)

Agentic & Tool Use benchmarks
BenchmarkGemini 2.5 FlashGPT-5
Terminal-Bench17.1%49.6%
BALROG33.5%32.8%
Berkeley Function Calling Leaderboard56.2%—
GDPval—34.8%
Remote Labor Index—1.7%
TheAgentCompany41.1%—
DeepResearch Bench—49.6%
LMArena Search—1133
METR Time Horizons—69.6%
Vending-Bench 2548.84—

Reasoning GPT-5 leads

Gemini 2.5 Flash: 18.1 (#286), GPT-5: 38.3 (#64)

Reasoning benchmarks
BenchmarkGemini 2.5 FlashGPT-5
ARC-AGI-22.5%9.9%
SimpleBench41.2%56.7%
Kagi LLM Benchmark56.8%72.7%
ARC-AGI-133.3%65.7%
CritPt1.1%12.6%
EnigmaEval2.7%10.5%
LMArena Hard Prompts14221416
DTBench76.5%90.7%
LMCA27.5%40%
Epoch Capabilities Index143.03150
ForecastBench60.661.4
Chess Puzzles—37%
EBR-Bench—12.7%
Mystery Game Puzzles—23%

Math GPT-5 leads

Gemini 2.5 Flash: 39.9 (#98), GPT-5: 55.0 (#44)

Math benchmarks
BenchmarkGemini 2.5 FlashGPT-5
OTIS Mock AIME 2024-202573.1%91.4%
Omni-MATH38.5%64.7%
LMArena Math14151407
FrontierMath (Feb 2025 set)4.8%32.4%
FrontierMath Tier 4 (v1)4.2%12.5%
FrontierMath (Tiers 1-3)—55.4%
FrontierMath Tier 4—22%
ProofBench—18%
MATH Level 5—98.1%

Knowledge GPT-5 leads

Gemini 2.5 Flash: 36.4 (#168), GPT-5: 56.6 (#43)

Knowledge benchmarks
BenchmarkGemini 2.5 FlashGPT-5
Humanity's Last Exam12.1%25.3%
MMLU-Pro63.9%86.3%
Confabulations16.8%10.3%
Vectara Hallucination Rate7.8%14.7%
GPQA (HELM)39%79.2%
LMArena Expert14261419
GPQA Diamond—86.2%
SimpleQA Verified—50.1%

Multimodal GPT-5 leads

Gemini 2.5 Flash: 41.8 (#32), GPT-5: 46.8 (#13)

Multimodal benchmarks
BenchmarkGemini 2.5 FlashGPT-5
LMArena Vision12531232
GeoBench76%81%
VPCT46.2%66%
SpatialViz-Bench36.9%—

Multilingual Too close to call

Gemini 2.5 Flash: 52.3 (#88), GPT-5: 51.4 (#110)

Multilingual benchmarks
BenchmarkGemini 2.5 FlashGPT-5
LMArena Non-English14091397
LMArena Chinese14501422
LMArena French14331410
LMArena German14181416
LMArena Japanese14051409
LMArena Korean13851360
LMArena Russian14151406
LMArena Spanish14211399

Instruction Following Gemini 2.5 Flash leads

Gemini 2.5 Flash: 75.7 (#54), GPT-5: 73.8 (#113)

Instruction Following benchmarks
BenchmarkGemini 2.5 FlashGPT-5
IFEval89.8%87.5%
LMArena Instruction Following14051388

Long Context GPT-5 leads

Gemini 2.5 Flash: 47.5 (#17), GPT-5: 69.5 (#2)

Long Context benchmarks
BenchmarkGemini 2.5 FlashGPT-5
Fiction.LiveBench77.8%97.2%
LMArena Longer Query14191399

Writing & Preference GPT-5 leads

Gemini 2.5 Flash: 53.8 (#157), GPT-5: 63.4 (#65)

Writing & Preference benchmarks
BenchmarkGemini 2.5 FlashGPT-5
LMArena Text14171406
LMArena Creative Writing14001365
Short-Story Creative Writing76.5%86%
EQ-Bench Creative Writing11371627
WildBench81.7%85.7%
LMArena Multi-Turn14081426

Frequently asked questions

Is Gemini 2.5 Flash better than GPT-5?

GPT-5 is the stronger model overall, scoring 50.9 to 39.3 on the Noometry Index. Gemini 2.5 Flash costs 4.0× less per token, which makes it the better buy when GPT-5's lead doesn't matter for your workload.

Which is cheaper, Gemini 2.5 Flash or GPT-5?

Gemini 2.5 Flash is cheaper. It lists at $0.30 per million input tokens and $2.50 per million output tokens; GPT-5 lists at $1.25 and $10.

Is Gemini 2.5 Flash or GPT-5 better for coding?

GPT-5 scores higher on coding benchmarks: 50.3 versus 35.8 in the Noometry coding category.

Which has the bigger context window?

Gemini 2.5 Flash does, with 1.05M tokens against 400K.

How many benchmarks do Gemini 2.5 Flash and GPT-5 share?

50 benchmarks have published results for both models. Gemini 2.5 Flash has 54 scored results on Noometry and GPT-5 has 69.

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