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Gemini 2.5 Flash vs GPT-5 Nano

Gemini 2.5 Flash leads GPT-5 Nano on the Artificial Analysis Intelligence Index, 15.5 to 13.0, and GPT-5 Nano costs 6.3x less per output token ($0.40 vs $2.50 per million). Updated October 21, 2026; 63 benchmarks have a result for both.

Replace Gemini 2.5 Flash Replace GPT-5 Nano
Gemini 2.5 FlashGoogle
Coding
No data
Overall
34.3
Output $/M
$2.50
49
GPT-5 NanoOpenAI
Coding
No data
Overall
35.6
Output $/M
$0.40
14
vs boards won of 63 shared

Gemini 2.5 Flash or GPT-5 Nano: which to pick

Neither model has a coding score yet, so the two cannot be ranked on coding.

Pick Gemini 2.5 Flash for a larger context window (1.05M against 400K tokens) and work measured by SWE-bench Verified or LiveCodeBench (Artificial Analysis run), where it leads.

Model AGemini 2.5 FlashGoogleNot benchmarkedNo coding benchmark$0.466 per solved taskModel BGPT-5 NanoOpenAINot benchmarkedNo coding benchmark$0.109 per solved task
Shared results
63
Gemini 2.5 Flash only
10
GPT-5 Nano only
24
Like-for-like categories
8 of 9

Only benchmarks that tested both models count toward a pick; a result only one model has is shown but not compared.

Which one for your work

Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.

At a glance

Coding index
Gemini 2.5 Flash not benchmarked, GPT-5 Nano not benchmarked.
Widest category
General, 17.1 points apart on average over 27 shared benchmarks.
Widest single gap
LMArena Text: Japanese: Gemini 2.5 Flash 1396 against GPT-5 Nano 1227, 28.3 points apart on a 0 to 100 scale.
Output price
Gemini 2.5 Flash $2.50 against GPT-5 Nano $0.40 per million output tokens, 6.3x apart.
Context window
Gemini 2.5 Flash takes 1.05M tokens, GPT-5 Nano 400K.

Benchmark by benchmark

First the score: boards each model leads, per category, where both have a result. Then every board, a category to a fold; bars are each result on a 0 to 100 scale, so compare the two in a row, not one row with another.

Boards won, where both have a result
CategoryGemini 2.5 FlashBarsGPT-5 NanoTies
Coding24
Intelligence20
Agentic work11
Reasoning82
Math22
Knowledge60
Web design24
General261
All shared boards4914
CodingLike-for-likeSix of these boards feed the Vibe Coding Index24
Coding benchmarks for Gemini 2.5 Flash and GPT-5 Nano
BenchmarkGemini 2.5 FlashGPT-5 NanoLeader
SWE-bench Verified28.7%34.8%GPT-5 Nano
LiveCodeBench (Vals AI)Not measured70.2%Only GPT-5 Nano measured
LiveCodeBench (Artificial Analysis run)69.5%78.9%GPT-5 Nano
Terminal-Bench Hard (Artificial Analysis run)13.6%17.4%GPT-5 Nano
Terminal-Bench17.1%21.8%GPT-5 Nano
WeirdMLNot measured38.1%Only GPT-5 Nano measured
LMArena Text: coding14231351Gemini 2.5 Flash
LMArena Text: software and IT14251345Gemini 2.5 Flash
Neither model has a result on the other 31 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
Intelligence benchmarks for Gemini 2.5 Flash and GPT-5 Nano
BenchmarkGemini 2.5 FlashGPT-5 NanoLeader
AA Intelligence Index15.513.0Gemini 2.5 Flash
Epoch Capabilities Index142.9139.2Gemini 2.5 Flash
Agentic workLike-for-likePublic boards, shown as published, kept out of the index11
Agentic work benchmarks for Gemini 2.5 Flash and GPT-5 Nano
BenchmarkGemini 2.5 FlashGPT-5 NanoLeader
τ²-Bench Telecom31.6%36.5%GPT-5 Nano
BALROG33.5%Not measuredOnly Gemini 2.5 Flash measured
Vending-Bench 2$549Not measuredOnly Gemini 2.5 Flash measured
Berkeley Function Calling Leaderboard (BFCL)56.2%51.4%Gemini 2.5 Flash
BrowseComp-Plus39.9%Not measuredOnly Gemini 2.5 Flash measured
Neither model has a result on the other 36 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index82
Reasoning benchmarks for Gemini 2.5 Flash and GPT-5 Nano
BenchmarkGemini 2.5 FlashGPT-5 NanoLeader
GPQA DiamondNot measured63.4%Only GPT-5 Nano measured
MMMU Pro (Vals AI)Not measured70.9%Only GPT-5 Nano measured
GPQA Diamond (Artificial Analysis run)79.0%67.6%Gemini 2.5 Flash
Humanity's Last Exam (Artificial Analysis run)12.1%9.5%Gemini 2.5 Flash
GPQA Diamond (Epoch AI run)Not measured69.4%Only GPT-5 Nano measured
ARC-AGI33.3%20.7%Gemini 2.5 Flash
ARC-AGI-22.5%2.6%GPT-5 Nano
SimpleBench41.2%Not measuredOnly Gemini 2.5 Flash measured
Chess puzzlesNot measured22.0%Only GPT-5 Nano measured
Mystery game puzzlesNot measured9.0%Only GPT-5 Nano measured
VPCTNot measured37.2%Only GPT-5 Nano measured
LMArena Text: hard prompts14221328Gemini 2.5 Flash
LMArena Text: expert14261321Gemini 2.5 Flash
LMArena Text: hard prompts in English14201338Gemini 2.5 Flash
LMArena Vision: diagrams12451141Gemini 2.5 Flash
LMArena Vision: homework12441157Gemini 2.5 Flash
Kagi LLM Benchmark56.8%62.2%GPT-5 Nano
Neither model has a result on the other 5 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index22
Math benchmarks for Gemini 2.5 Flash and GPT-5 Nano
BenchmarkGemini 2.5 FlashGPT-5 NanoLeader
AIMENot measured81.2%Only GPT-5 Nano measured
MATH 500 (Vals AI)Not measured93.8%Only GPT-5 Nano measured
MGSM (Vals AI)Not measured89.3%Only GPT-5 Nano measured
AA Math Index73.383.7GPT-5 Nano
AIME 2025 (Artificial Analysis run)73.3%83.7%GPT-5 Nano
OTIS Mock AIMENot measured81.1%Only GPT-5 Nano measured
FrontierMath, tiers 1 to 3Not measured20.0%Only GPT-5 Nano measured
FrontierMath, tier 4Not measured2.4%Only GPT-5 Nano measured
ProofBenchNot measured12.0%Only GPT-5 Nano measured
MATH level 5Not measured95.2%Only GPT-5 Nano measured
LMArena Text: math14111317Gemini 2.5 Flash
LMArena Text: mathematical work14221326Gemini 2.5 Flash
Neither model has a result on the other 1 board here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index60
Knowledge benchmarks for Gemini 2.5 Flash and GPT-5 Nano
BenchmarkGemini 2.5 FlashGPT-5 NanoLeader
MMLU ProNot measured76.1%Only GPT-5 Nano measured
LegalBench (Vals AI)Not measured50.1%Only GPT-5 Nano measured
CaseLaw (Vals AI)Not measured52.6%Only GPT-5 Nano measured
TaxEval (Vals AI)Not measured67.4%Only GPT-5 Nano measured
MortgageTax (Vals AI)Not measured53.6%Only GPT-5 Nano measured
MedQA (Vals AI)Not measured93.3%Only GPT-5 Nano measured
MedCode (Vals AI)40.4%30.4%Gemini 2.5 Flash
MMLU Pro (Artificial Analysis run)83.2%78.0%Gemini 2.5 Flash
SimpleQA VerifiedNot measured11.7%Only GPT-5 Nano measured
LMArena Text: science14331318Gemini 2.5 Flash
LMArena Text: medicine and healthcare14281335Gemini 2.5 Flash
LMArena Text: legal and government14301298Gemini 2.5 Flash
LMArena Text: business and finance14041311Gemini 2.5 Flash
FACTS Benchmark Suite47.2%Not measuredOnly Gemini 2.5 Flash measured
Neither model has a result on the other 4 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index24
Web design benchmarks for Gemini 2.5 Flash and GPT-5 Nano
BenchmarkGemini 2.5 FlashGPT-5 NanoLeader
Design Arena: websites10741101GPT-5 Nano
Design Arena: UI components10051067GPT-5 Nano
Design Arena: game dev10051045GPT-5 Nano
Design Arena: data viz10601056Gemini 2.5 Flash
Design Arena: 3D1021966Gemini 2.5 Flash
Design Arena: all code categories10591084GPT-5 Nano
Design Arena: SVG1020Not measuredOnly Gemini 2.5 Flash measured
Neither model has a result on the other 2 boards here
GeneralLike-for-likePublic boards, shown as published, kept out of the index261
General benchmarks for Gemini 2.5 Flash and GPT-5 Nano
BenchmarkGemini 2.5 FlashGPT-5 NanoLeader
SAGE (Vals AI)44.8%30.4%Gemini 2.5 Flash
MedScribe (Vals AI)83.0%72.9%Gemini 2.5 Flash
IFBench50.3%67.6%GPT-5 Nano
Long context reasoning (AA-LCR)65.3%45.0%Gemini 2.5 Flash
DTBench76.5%62.7%Gemini 2.5 Flash
LMCA27.5%7.9%Gemini 2.5 Flash
Fiction.LiveBenchNot measured44.4%Only GPT-5 Nano measured
LMArena Text14171320Gemini 2.5 Flash
LMArena Text: instruction following14051306Gemini 2.5 Flash
LMArena Text: creative writing14001249Gemini 2.5 Flash
LMArena Vision12351159Gemini 2.5 Flash
LMArena Text: English14181321Gemini 2.5 Flash
LMArena Text: non-English14091313Gemini 2.5 Flash
LMArena Text: Chinese14491356Gemini 2.5 Flash
LMArena Text: German14171327Gemini 2.5 Flash
LMArena Text: Japanese13961227Gemini 2.5 Flash
LMArena Text: Korean13851269Gemini 2.5 Flash
LMArena Text: French1432Not measuredOnly Gemini 2.5 Flash measured
LMArena Text: Spanish14221360Gemini 2.5 Flash
LMArena Text: Russian14151296Gemini 2.5 Flash
LMArena Text: Polish14131314Gemini 2.5 Flash
LMArena Text: multi-turn14081311Gemini 2.5 Flash
LMArena Text: longer queries14191312Gemini 2.5 Flash
LMArena Text: writing and language14051283Gemini 2.5 Flash
LMArena Text: entertainment and media13931268Gemini 2.5 Flash
LMArena Vision: English12391170Gemini 2.5 Flash
LMArena Vision: Chinese12841176Gemini 2.5 Flash
LMArena Vision: reading text12371152Gemini 2.5 Flash
LMArena Vision: humor12251110Gemini 2.5 Flash
LMArena Vision: captioning1277Not measuredOnly Gemini 2.5 Flash measured
LMArena Vision: recognizing things1252Not measuredOnly Gemini 2.5 Flash measured
LMArena Vision: creative writing1241Not measuredOnly Gemini 2.5 Flash measured
Neither model has a result on the other 14 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for Gemini 2.5 Flash and GPT-5 Nano
BenchmarkGemini 2.5 FlashGPT-5 NanoLeader
Neither model has a result on 5 boards here

What each workload costs

Three fixed token mixes at each model's listed price, so per-token rates become a bill.

Chat turn

1K input + 500 output tokens

Gemini 2.5 Flash$0.0015Fits in one request
GPT-5 Nano$0.0003Fits in one request

GPT-5 Nano costs less

Repository review

50K input + 3K output tokens

Gemini 2.5 Flash$0.022Fits in one request
GPT-5 Nano$0.0037Fits in one request

GPT-5 Nano costs less

Agent loop

200K input + 10K output tokens

Gemini 2.5 Flash$0.085Fits in one request
GPT-5 Nano$0.014Fits in one request

GPT-5 Nano costs less

Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.

Specification differences

The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.

Specifications of Gemini 2.5 Flash and GPT-5 Nano
SpecificationGoogle Gemini 2.5 FlashOpenAI GPT-5 Nano
MakerGoogleOpenAI
WeightsNo public weights listedNo public weights listed
ReleasedJune 17, 2025August 7, 2025
Context window1.05M400K
Input $/Mtok$0.30$0.05
Output $/Mtok$2.50$0.40
Coding indexNot benchmarkedNot benchmarked
Independent measurements behind it00
Cost per solved task$0.466$0.109
SourceOpenRouter listingOpenRouter listing

Questions

Is Gemini 2.5 Flash better than GPT-5 Nano for coding?

Neither model has a coding score yet, so the two cannot be ranked on coding. Pick Gemini 2.5 Flash for a larger context window (1.05M against 400K tokens) and work measured by SWE-bench Verified or LiveCodeBench (Artificial Analysis run), where it leads.

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

Gemini 2.5 Flash costs $0.30 per million input tokens and $2.50 per million output tokens; GPT-5 Nano costs $0.05 and $0.40. Per solved SWE-bench Verified task, Gemini 2.5 Flash costs $0.466 and GPT-5 Nano $0.109.

Which has the bigger context window, Gemini 2.5 Flash or GPT-5 Nano?

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

How many benchmarks is the Gemini 2.5 Flash vs GPT-5 Nano comparison based on?

63 benchmarks have a result for both models as of October 21, 2026. Gemini 2.5 Flash's coding index rests on 0 independent benchmarks and GPT-5 Nano's on 0. Where only one model has a result, the page says so instead of naming a winner.

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