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Gemini 3.6 Flash vs GPT-6 Luna

Gemini 3.6 Flash leads GPT-6 Luna on coding, 62.5 to 57.3 on the Vibe Coding Index, and GPT-6 Luna costs 7.5x less per output token ($0.50 vs $3.75 per million). Updated October 22, 2026; 87 benchmarks have a result for both.

Replace Gemini 3.6 Flash Replace GPT-6 Luna
Gemini 3.6 FlashGoogle
Coding
62.5
Overall
68.3
Output $/M
$3.75
59
GPT-6 LunaOpenAI
Coding
57.3
Overall
59.7
Output $/M
$0.50
26
vs boards won of 87 shared, 2 tied

Gemini 3.6 Flash or GPT-6 Luna: which to pick

Pick Gemini 3.6 Flash for coding: it scores 62.5 on the Vibe Coding Index against 57.3 for GPT-6 Luna, though on 4 benchmarks against 5.

Pick GPT-6 Luna for output tokens 7.5x cheaper ($0.50 vs $3.75 per million) and a larger context window (1.05M against 1.05M tokens).

Model AGemini 3.6 FlashGoogle62.5/1004 independent benchmarks$1.49 per solved taskModel BGPT-6 LunaOpenAI57.3/1005 independent benchmarksNo cost per solved task
Shared results
87
Gemini 3.6 Flash only
23
GPT-6 Luna only
17
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 3.6 Flash 62.5 from 4 benchmarks, GPT-6 Luna 57.3 from 5 benchmarks.
Widest category
Math, 19.0 points apart on average over 6 shared benchmarks.
Widest single gap
FrontierMath, tier 4: Gemini 3.6 Flash 22.0% against GPT-6 Luna 56.1%, 34.1 points apart on a 0 to 100 scale.
Output price
Gemini 3.6 Flash $3.75 against GPT-6 Luna $0.50 per million output tokens, 7.5x apart.
Context window
Gemini 3.6 Flash takes 1.05M tokens, GPT-6 Luna 1.05M.

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 3.6 FlashBarsGPT-6 LunaTies
Coding312
Intelligence02
Agentic work541 tie
Reasoning110
Math24
Knowledge70
Web design601 tie
General254
All shared boards59262 ties
CodingLike-for-likeSix of these boards feed the Vibe Coding Index312
Coding benchmarks for Gemini 3.6 Flash and GPT-6 Luna
BenchmarkGemini 3.6 FlashGPT-6 LunaLeader
LiveBench codingNot measured84.5%Only GPT-6 Luna measured
LMArena WebDev15381578GPT-6 Luna
AA Coding Index69.2Not measuredOnly Gemini 3.6 Flash measured
LiveCodeBench (Vals AI)88.1%Not measuredOnly Gemini 3.6 Flash measured
SWE-bench Verified (Vals AI)79.6%Not measuredOnly Gemini 3.6 Flash measured
Terminal-Bench 4 (Vals AI)Not measured13.6%Only GPT-6 Luna measured
Vibe Code Bench (Vals AI)64.0%81.7%GPT-6 Luna
Code migration (Vals AI)30.9%42.5%GPT-6 Luna
ProgramBench (Vals AI)0.0%0.5%GPT-6 Luna
IOI (Vals AI)35.1%55.6%GPT-6 Luna
Terminal-Bench 2.1 (Vals AI)73.8%73.0%Gemini 3.6 Flash
SWE-bench Multimodal (Vals AI)Not measured37.5%Only GPT-6 Luna measured
CyberBench (Vals AI)45.4%76.3%GPT-6 Luna
SciCode53.4%54.6%GPT-6 Luna
FrontierCode34.4%42.4%GPT-6 Luna
WeirdML56.1%Not measuredOnly Gemini 3.6 Flash measured
ALE-Bench715.51576.9GPT-6 Luna
LMArena Text: coding14911437Gemini 3.6 Flash
LMArena Text: software and IT14921423Gemini 3.6 Flash
LMArena WebDev: React15281573GPT-6 Luna
LMArena WebDev: HTML15471595GPT-6 Luna
LMArena WebDev: from an image15451571GPT-6 Luna
SciCode10.8%Not measuredOnly Gemini 3.6 Flash measured
Neither model has a result on the other 20 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02
Intelligence benchmarks for Gemini 3.6 Flash and GPT-6 Luna
BenchmarkGemini 3.6 FlashGPT-6 LunaLeader
AA Intelligence Index34.038.1GPT-6 Luna
Epoch Capabilities Index154.5156.8GPT-6 Luna
Agentic workLike-for-likePublic boards, shown as published, kept out of the index54
Agentic work benchmarks for Gemini 3.6 Flash and GPT-6 Luna
BenchmarkGemini 3.6 FlashGPT-6 LunaLeader
AA Agentic Index29.0Not measuredOnly Gemini 3.6 Flash measured
Design Arena: agents building web apps11971191Gemini 3.6 Flash
Design Arena: agents building full-stack apps11811158Gemini 3.6 Flash
Design Arena: agents building mobile apps11961131Gemini 3.6 Flash
Design Arena: agents building Android apps1203Not measuredOnly Gemini 3.6 Flash measured
Design Arena: agents building games1180Not measuredOnly Gemini 3.6 Flash measured
Design Arena: HTML slides1088Not measuredOnly Gemini 3.6 Flash measured
Design Arena: PowerPoint slides1118Not measuredOnly Gemini 3.6 Flash measured
Design Arena: spreadsheets1072Not measuredOnly Gemini 3.6 Flash measured
LiveBench researchNot measured43.5%Only GPT-6 Luna measured
LiveBench browserNot measured72.0%Only GPT-6 Luna measured
LiveBench long agenticNot measured48.1%Only GPT-6 Luna measured
SREBench (Vals AI)Not measured2.7%Only GPT-6 Luna measured
Finance Agent (Vals AI)56.3%49.9%Gemini 3.6 Flash
Tax Agent Bench (Vals AI)18.0%19.9%GPT-6 Luna
Legal Research Bench (Vals AI)25.0%30.3%GPT-6 Luna
Harvey's Legal Agent Benchmark (Vals AI)Not measured4.2%Only GPT-6 Luna measured
Excel Modeling Benchmark (Vals AI)65.4%68.5%GPT-6 Luna
BioMysteryBench (Vals AI)58.5%61.5%GPT-6 Luna
Terminal-Bench-Science (Vals AI)4.3%4.3%Tie
Vals Science IndexNot measured28.4%Only GPT-6 Luna measured
APEX-Agents46.9%44.3%Gemini 3.6 Flash
SpireClimbNot measured0.0%Only GPT-6 Luna measured
Neither model has a result on the other 19 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index110
Reasoning benchmarks for Gemini 3.6 Flash and GPT-6 Luna
BenchmarkGemini 3.6 FlashGPT-6 LunaLeader
GPQA Diamond93.4%Not measuredOnly Gemini 3.6 Flash measured
LiveBench reasoningNot measured81.8%Only GPT-6 Luna measured
MysteryMechanism (Vals AI)Not measured19.4%Only GPT-6 Luna measured
MMMU Pro (Vals AI)88.4%Not measuredOnly Gemini 3.6 Flash measured
GPQA Diamond (Artificial Analysis run)92.8%Not measuredOnly Gemini 3.6 Flash measured
Humanity's Last Exam (Artificial Analysis run)40.8%38.5%Gemini 3.6 Flash
GPQA Diamond (Epoch AI run)94.1%90.5%Gemini 3.6 Flash
ARC-AGI91.2%86.7%Gemini 3.6 Flash
ARC-AGI-260.4%59.3%Gemini 3.6 Flash
Chess puzzles42.0%36.0%Gemini 3.6 Flash
Mystery game puzzles30.0%7.0%Gemini 3.6 Flash
LMArena Text: hard prompts14861410Gemini 3.6 Flash
LMArena Text: expert14901442Gemini 3.6 Flash
LMArena Text: hard prompts in English14841410Gemini 3.6 Flash
LMArena Vision: diagrams13141245Gemini 3.6 Flash
LMArena Vision: homework13141261Gemini 3.6 Flash
Neither model has a result on the other 7 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index24
Math benchmarks for Gemini 3.6 Flash and GPT-6 Luna
BenchmarkGemini 3.6 FlashGPT-6 LunaLeader
OTIS Mock AIME94.2%98.9%GPT-6 Luna
FrontierMath, tiers 1 to 358.9%78.9%GPT-6 Luna
FrontierMath, tier 422.0%56.1%GPT-6 Luna
ProofBench36.0%64.0%GPT-6 Luna
LMArena Text: math15081409Gemini 3.6 Flash
LMArena Text: mathematical work14921427Gemini 3.6 Flash
MathArena23.9%Not measuredOnly Gemini 3.6 Flash measured
Neither model has a result on the other 7 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index70
Knowledge benchmarks for Gemini 3.6 Flash and GPT-6 Luna
BenchmarkGemini 3.6 FlashGPT-6 LunaLeader
MMLU Pro89.3%Not measuredOnly Gemini 3.6 Flash measured
LegalBench (Vals AI)86.7%Not measuredOnly Gemini 3.6 Flash measured
CorpFin (Vals AI)63.3%Not measuredOnly Gemini 3.6 Flash measured
TaxEval (Vals AI)74.9%Not measuredOnly Gemini 3.6 Flash measured
MortgageTax (Vals AI)67.6%Not measuredOnly Gemini 3.6 Flash measured
MedCode (Vals AI)53.1%44.7%Gemini 3.6 Flash
SimpleQA Verified66.2%41.4%Gemini 3.6 Flash
LMArena Text: science14891386Gemini 3.6 Flash
LMArena Text: medicine and healthcare14691352Gemini 3.6 Flash
LMArena Text: legal and government14791400Gemini 3.6 Flash
LMArena Text: business and finance14641388Gemini 3.6 Flash
FACTS Benchmark Suite65.3%63.3%Gemini 3.6 Flash
PRBench LegalNot measured42.9%Only GPT-6 Luna measured
Neither model has a result on the other 7 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index60
Web design benchmarks for Gemini 3.6 Flash and GPT-6 Luna
BenchmarkGemini 3.6 FlashGPT-6 LunaLeader
Design Arena: websites13001271Gemini 3.6 Flash
Design Arena: UI components12951295Tie
Design Arena: game dev12631258Gemini 3.6 Flash
Design Arena: data viz12891217Gemini 3.6 Flash
Design Arena: 3D12711218Gemini 3.6 Flash
Design Arena: all code categories12891270Gemini 3.6 Flash
Design Arena: SVGNot measured1253Only GPT-6 Luna measured
Design Arena: ASCII art12811153Gemini 3.6 Flash
LiveBench designNot measured82.5%Only GPT-6 Luna measured
GeneralLike-for-likePublic boards, shown as published, kept out of the index254
General benchmarks for Gemini 3.6 Flash and GPT-6 Luna
BenchmarkGemini 3.6 FlashGPT-6 LunaLeader
Vals IndexNot measured52.3%Only GPT-6 Luna measured
LiveBench data analysisNot measured73.4%Only GPT-6 Luna measured
Public Benefits Bench (Vals AI)56.6%57.6%GPT-6 Luna
SAGE (Vals AI)48.7%48.1%Gemini 3.6 Flash
MedScribe (Vals AI)79.7%83.7%GPT-6 Luna
Vals Multimodal Index65.1%Not measuredOnly Gemini 3.6 Flash measured
Long context reasoning (AA-LCR)80.0%83.3%GPT-6 Luna
DTBench95.5%90.1%Gemini 3.6 Flash
LMCA44.9%44.5%Gemini 3.6 Flash
Furniture assembly23.3%44.2%GPT-6 Luna
LMArena Text14801389Gemini 3.6 Flash
LMArena Text: instruction following14671408Gemini 3.6 Flash
LMArena Text: creative writing14661363Gemini 3.6 Flash
LMArena Vision12991216Gemini 3.6 Flash
LMArena Text: English14821393Gemini 3.6 Flash
LMArena Text: non-English14701381Gemini 3.6 Flash
LMArena Text: Chinese15311427Gemini 3.6 Flash
LMArena Text: German14801376Gemini 3.6 Flash
LMArena Text: Japanese14751369Gemini 3.6 Flash
LMArena Text: Korean14291359Gemini 3.6 Flash
LMArena Text: French15031408Gemini 3.6 Flash
LMArena Text: Spanish14761391Gemini 3.6 Flash
LMArena Text: Russian14881392Gemini 3.6 Flash
LMArena Text: Polish14731383Gemini 3.6 Flash
LMArena Text: multi-turn14811392Gemini 3.6 Flash
LMArena Text: longer queries14751408Gemini 3.6 Flash
LMArena Text: writing and language14701384Gemini 3.6 Flash
LMArena Text: entertainment and media14561364Gemini 3.6 Flash
LMArena Vision: English12951204Gemini 3.6 Flash
LMArena Vision: Chinese13571266Gemini 3.6 Flash
LMArena Vision: reading text13121225Gemini 3.6 Flash
LMArena Vision: humor1289Not measuredOnly Gemini 3.6 Flash measured
LMArena Vision: creative writing12781205Gemini 3.6 Flash
LMArena Document1456Not measuredOnly Gemini 3.6 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 3.6 Flash and GPT-6 Luna
BenchmarkGemini 3.6 FlashGPT-6 LunaLeader
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 3.6 Flash$0.0026Fits in one request
GPT-6 Luna$0.0003Fits in one request

GPT-6 Luna costs less

Repository review

50K input + 3K output tokens

Gemini 3.6 Flash$0.049Fits in one request
GPT-6 Luna$0.0065Fits in one request

GPT-6 Luna costs less

Agent loop

200K input + 10K output tokens

Gemini 3.6 Flash$0.188Fits in one request
GPT-6 Luna$0.025Fits in one request

GPT-6 Luna 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 3.6 Flash and GPT-6 Luna
SpecificationGoogle Gemini 3.6 FlashOpenAI GPT-6 Luna
MakerGoogleOpenAI
WeightsNo public weights listedNo public weights listed
ReleasedJuly 21, 2026September 22, 2026
Context window1.05M1.05M
Input $/Mtok$0.75$0.10
Output $/Mtok$3.75$0.50
Coding index62.557.3
Independent measurements behind it45
Cost per solved task$1.49Not computable
SourceOpenRouter listingOpenRouter listing

Questions

Is Gemini 3.6 Flash better than GPT-6 Luna for coding?

Pick Gemini 3.6 Flash for coding: it scores 62.5 on the Vibe Coding Index against 57.3 for GPT-6 Luna, though on 4 benchmarks against 5. Pick GPT-6 Luna for output tokens 7.5x cheaper ($0.50 vs $3.75 per million) and a larger context window (1.05M against 1.05M tokens).

Which is cheaper, Gemini 3.6 Flash or GPT-6 Luna?

Gemini 3.6 Flash costs $0.75 per million input tokens and $3.75 per million output tokens; GPT-6 Luna costs $0.10 and $0.50. Cost per solved task is known for Gemini 3.6 Flash only.

Which has the bigger context window, Gemini 3.6 Flash or GPT-6 Luna?

GPT-6 Luna, with 1.05M tokens against 1.05M.

How many benchmarks is the Gemini 3.6 Flash vs GPT-6 Luna comparison based on?

87 benchmarks have a result for both models as of October 22, 2026. Gemini 3.6 Flash's coding index rests on 4 independent benchmarks and GPT-6 Luna's on 5. Where only one model has a result, the page says so instead of naming a winner.

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<p style="font:13px/1.4 sans-serif;margin:6px 0 0">Source: <a href="https://llmbenchmark.ai/compare/gemini-3-6-flash-vs-gpt-6-luna">LLMBenchmark.ai, Gemini 3.6 Flash vs GPT-6 Luna</a></p>