Enter opens the highlighted result. Esc closes.

Gemini 3.6 Flash vs GPT-5.6 Luna

Gemini 3.6 Flash leads GPT-5.6 Luna on coding, 62.5 to 58.0 on the Vibe Coding Index, and GPT-5.6 Luna costs 3.1x less per output token ($1.20 vs $3.75 per million). Updated October 22, 2026; 100 benchmarks have a result for both.

Replace Gemini 3.6 Flash Replace GPT-5.6 Luna
Gemini 3.6 FlashGoogle
Coding
62.5
Overall
68.3
Output $/M
$3.75
67
GPT-5.6 LunaOpenAI
Coding
58.0
Overall
61.6
Output $/M
$1.20
32
vs boards won of 100 shared, 1 tied

Gemini 3.6 Flash or GPT-5.6 Luna: which to pick

Pick Gemini 3.6 Flash for coding: it scores 62.5 on the Vibe Coding Index against 58.0 for GPT-5.6 Luna, though on 4 benchmarks against 6.

Pick GPT-5.6 Luna for output tokens 3.1x cheaper ($1.20 vs $3.75 per million) and a lower cost per solved task ($0.04 against $1.49).

Model AGemini 3.6 FlashGoogle62.5/1004 independent benchmarks$1.49 per solved taskModel BGPT-5.6 LunaOpenAI58.0/1006 independent benchmarks$0.04 per solved task
Shared results
100
Gemini 3.6 Flash only
9
GPT-5.6 Luna only
19
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-5.6 Luna 58.0 from 6 benchmarks.
Widest category
Math, 17.0 points apart on average over 6 shared benchmarks.
Widest single gap
FrontierMath, tier 4: Gemini 3.6 Flash 22.0% against GPT-5.6 Luna 61.0%, 39.0 points apart on a 0 to 100 scale.
Output price
Gemini 3.6 Flash $3.75 against GPT-5.6 Luna $1.20 per million output tokens, 3.1x apart.
Context window
Gemini 3.6 Flash takes 1.05M tokens, GPT-5.6 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-5.6 LunaTies
Coding7111 tie
Intelligence02
Agentic work35
Reasoning131
Math24
Knowledge102
Web design70
General257
All shared boards67321 tie
CodingLike-for-likeSix of these boards feed the Vibe Coding Index711
Coding benchmarks for Gemini 3.6 Flash and GPT-5.6 Luna
BenchmarkGemini 3.6 FlashGPT-5.6 LunaLeader
LiveBench codingNot measured73.6%Only GPT-5.6 Luna measured
LMArena WebDev15381518Gemini 3.6 Flash
AA Coding Index69.271.4GPT-5.6 Luna
LiveCodeBench (Vals AI)88.1%Not measuredOnly Gemini 3.6 Flash measured
SWE-bench Verified (Vals AI)79.6%93.0%GPT-5.6 Luna
Terminal-Bench 4 (Vals AI)Not measured11.6%Only GPT-5.6 Luna measured
Vibe Code Bench (Vals AI)64.0%77.1%GPT-5.6 Luna
Code migration (Vals AI)30.9%44.5%GPT-5.6 Luna
ProgramBench (Vals AI)0.0%0.0%Tie
IOI (Vals AI)35.1%61.8%GPT-5.6 Luna
Terminal-Bench 2.1 (Vals AI)73.8%79.0%GPT-5.6 Luna
Vibe Code Bench 1-100 (Vals AI)Not measured22.6%Only GPT-5.6 Luna measured
SkillsBench (Vals AI)Not measured60.5%Only GPT-5.6 Luna measured
CyberBench (Vals AI)45.4%73.6%GPT-5.6 Luna
SciCode53.4%53.6%GPT-5.6 Luna
FrontierCode34.4%39.8%GPT-5.6 Luna
WeirdML56.1%60.9%GPT-5.6 Luna
ALE-Bench715.51667.4GPT-5.6 Luna
LMArena Text: coding14911466Gemini 3.6 Flash
LMArena Text: software and IT14921463Gemini 3.6 Flash
LMArena WebDev: React15281508Gemini 3.6 Flash
LMArena WebDev: HTML15471520Gemini 3.6 Flash
LMArena WebDev: from an image15451517Gemini 3.6 Flash
SciCode10.8%6.2%Gemini 3.6 Flash
Neither model has a result on the other 15 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02
Intelligence benchmarks for Gemini 3.6 Flash and GPT-5.6 Luna
BenchmarkGemini 3.6 FlashGPT-5.6 LunaLeader
AA Intelligence Index34.037.3GPT-5.6 Luna
Epoch Capabilities Index154.5156.5GPT-5.6 Luna
Agentic workLike-for-likePublic boards, shown as published, kept out of the index35
Agentic work benchmarks for Gemini 3.6 Flash and GPT-5.6 Luna
BenchmarkGemini 3.6 FlashGPT-5.6 LunaLeader
AA Agentic Index29.042.1GPT-5.6 Luna
Design Arena: agents building web apps1197Not measuredOnly Gemini 3.6 Flash measured
Design Arena: agents building full-stack apps1181Not measuredOnly Gemini 3.6 Flash measured
Design Arena: agents building mobile apps1198Not measuredOnly Gemini 3.6 Flash measured
Design Arena: agents building Android apps1204Not measuredOnly Gemini 3.6 Flash measured
Design Arena: agents building games1180Not measuredOnly Gemini 3.6 Flash measured
Design Arena: HTML slides1099Not measuredOnly Gemini 3.6 Flash measured
Design Arena: PowerPoint slides1121Not measuredOnly Gemini 3.6 Flash measured
Design Arena: spreadsheets1071Not measuredOnly Gemini 3.6 Flash measured
LiveBench researchNot measured51.0%Only GPT-5.6 Luna measured
LiveBench browserNot measured68.0%Only GPT-5.6 Luna measured
LiveBench long agenticNot measured30.4%Only GPT-5.6 Luna measured
SREBench (Vals AI)Not measured1.5%Only GPT-5.6 Luna measured
Finance Agent (Vals AI)56.3%55.0%Gemini 3.6 Flash
Tax Agent Bench (Vals AI)18.0%24.8%GPT-5.6 Luna
Legal Research Bench (Vals AI)25.0%36.5%GPT-5.6 Luna
Excel Modeling Benchmark (Vals AI)65.4%67.1%GPT-5.6 Luna
BioMysteryBench (Vals AI)58.5%61.5%GPT-5.6 Luna
Terminal-Bench-Science (Vals AI)4.3%0.0%Gemini 3.6 Flash
Vals Science IndexNot measured25.3%Only GPT-5.6 Luna measured
APEX-Agents46.9%43.0%Gemini 3.6 Flash
BALROGNot measured45.6%Only GPT-5.6 Luna measured
Vending-Bench 2Not measured$4,095Only GPT-5.6 Luna measured
Neither model has a result on the other 18 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index131
Reasoning benchmarks for Gemini 3.6 Flash and GPT-5.6 Luna
BenchmarkGemini 3.6 FlashGPT-5.6 LunaLeader
GPQA Diamond93.4%91.7%Gemini 3.6 Flash
LiveBench reasoningNot measured85.6%Only GPT-5.6 Luna measured
MysteryMechanism (Vals AI)Not measured14.4%Only GPT-5.6 Luna measured
MMMU Pro (Vals AI)88.4%85.0%Gemini 3.6 Flash
GPQA Diamond (Artificial Analysis run)92.8%91.1%Gemini 3.6 Flash
Humanity's Last Exam (Artificial Analysis run)40.8%39.5%Gemini 3.6 Flash
GPQA Diamond (Epoch AI run)94.1%91.6%Gemini 3.6 Flash
ARC-AGI91.2%88.0%Gemini 3.6 Flash
ARC-AGI-260.4%59.5%Gemini 3.6 Flash
SimpleBenchNot measured46.8%Only GPT-5.6 Luna measured
Chess puzzles42.0%43.0%GPT-5.6 Luna
Mystery game puzzles30.0%21.0%Gemini 3.6 Flash
LMArena Text: hard prompts14861451Gemini 3.6 Flash
LMArena Text: expert14901478Gemini 3.6 Flash
LMArena Text: hard prompts in English14841460Gemini 3.6 Flash
LMArena Vision: diagrams13141273Gemini 3.6 Flash
LMArena Vision: homework13141282Gemini 3.6 Flash
Kagi LLM BenchmarkNot measured49.1%Only GPT-5.6 Luna measured
Neither model has a result on the other 4 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index24
Math benchmarks for Gemini 3.6 Flash and GPT-5.6 Luna
BenchmarkGemini 3.6 FlashGPT-5.6 LunaLeader
OTIS Mock AIME94.2%98.3%GPT-5.6 Luna
FrontierMath, tiers 1 to 358.9%82.1%GPT-5.6 Luna
FrontierMath, tier 422.0%61.0%GPT-5.6 Luna
ProofBench36.0%60.0%GPT-5.6 Luna
LMArena Text: math15081459Gemini 3.6 Flash
LMArena Text: mathematical work14921470Gemini 3.6 Flash
Neither model has a result on the other 7 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index102
Knowledge benchmarks for Gemini 3.6 Flash and GPT-5.6 Luna
BenchmarkGemini 3.6 FlashGPT-5.6 LunaLeader
MMLU Pro89.3%86.0%Gemini 3.6 Flash
LegalBench (Vals AI)86.7%84.0%Gemini 3.6 Flash
CorpFin (Vals AI)63.3%64.2%GPT-5.6 Luna
TaxEval (Vals AI)74.9%76.2%GPT-5.6 Luna
MortgageTax (Vals AI)67.6%67.3%Gemini 3.6 Flash
MedCode (Vals AI)53.1%42.4%Gemini 3.6 Flash
SimpleQA Verified66.2%41.0%Gemini 3.6 Flash
LMArena Text: science14891433Gemini 3.6 Flash
LMArena Text: medicine and healthcare14691399Gemini 3.6 Flash
LMArena Text: legal and government14791446Gemini 3.6 Flash
LMArena Text: business and finance14641439Gemini 3.6 Flash
FACTS Benchmark Suite65.3%35.0%Gemini 3.6 Flash
Neither model has a result on the other 6 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index70
Web design benchmarks for Gemini 3.6 Flash and GPT-5.6 Luna
BenchmarkGemini 3.6 FlashGPT-5.6 LunaLeader
Design Arena: websites13001255Gemini 3.6 Flash
Design Arena: UI components12941248Gemini 3.6 Flash
Design Arena: game dev12631194Gemini 3.6 Flash
Design Arena: data viz12891211Gemini 3.6 Flash
Design Arena: 3D12711121Gemini 3.6 Flash
Design Arena: all code categories12891231Gemini 3.6 Flash
Design Arena: SVGNot measured1194Only GPT-5.6 Luna measured
Design Arena: ASCII art12811142Gemini 3.6 Flash
LiveBench designNot measured76.0%Only GPT-5.6 Luna measured
GeneralLike-for-likePublic boards, shown as published, kept out of the index257
General benchmarks for Gemini 3.6 Flash and GPT-5.6 Luna
BenchmarkGemini 3.6 FlashGPT-5.6 LunaLeader
LiveBench data analysisNot measured78.0%Only GPT-5.6 Luna measured
Public Benefits Bench (Vals AI)56.6%61.2%GPT-5.6 Luna
SAGE (Vals AI)48.7%44.2%Gemini 3.6 Flash
MedScribe (Vals AI)79.7%84.4%GPT-5.6 Luna
Vals Multimodal Index65.1%69.1%GPT-5.6 Luna
Long context reasoning (AA-LCR)80.0%83.7%GPT-5.6 Luna
DTBench95.5%89.1%Gemini 3.6 Flash
LMCA44.9%48.5%GPT-5.6 Luna
Surface Evolver BenchNot measured61.9%Only GPT-5.6 Luna measured
Furniture assembly23.3%42.5%GPT-5.6 Luna
LMArena Text14801431Gemini 3.6 Flash
LMArena Text: instruction following14671437Gemini 3.6 Flash
LMArena Text: creative writing14661396Gemini 3.6 Flash
LMArena Vision12991257Gemini 3.6 Flash
LMArena Text: English14821441Gemini 3.6 Flash
LMArena Text: non-English14701417Gemini 3.6 Flash
LMArena Text: Chinese15311470Gemini 3.6 Flash
LMArena Text: German14801455Gemini 3.6 Flash
LMArena Text: Japanese14751415Gemini 3.6 Flash
LMArena Text: Korean14291415Gemini 3.6 Flash
LMArena Text: French15031458Gemini 3.6 Flash
LMArena Text: Spanish14761446Gemini 3.6 Flash
LMArena Text: Russian14881427Gemini 3.6 Flash
LMArena Text: Polish14731405Gemini 3.6 Flash
LMArena Text: multi-turn14811434Gemini 3.6 Flash
LMArena Text: longer queries14751436Gemini 3.6 Flash
LMArena Text: writing and language14701419Gemini 3.6 Flash
LMArena Text: entertainment and media14561402Gemini 3.6 Flash
LMArena Vision: English12951263Gemini 3.6 Flash
LMArena Vision: Chinese13571294Gemini 3.6 Flash
LMArena Vision: reading text13121264Gemini 3.6 Flash
LMArena Vision: humor12891190Gemini 3.6 Flash
LMArena Vision: creative writing12781257Gemini 3.6 Flash
LMArena Document14561457GPT-5.6 Luna
Neither model has a result on the other 12 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-5.6 Luna
BenchmarkGemini 3.6 FlashGPT-5.6 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-5.6 Luna$0.0008Fits in one request

GPT-5.6 Luna costs less

Repository review

50K input + 3K output tokens

Gemini 3.6 Flash$0.049Fits in one request
GPT-5.6 Luna$0.014Fits in one request

GPT-5.6 Luna costs less

Agent loop

200K input + 10K output tokens

Gemini 3.6 Flash$0.188Fits in one request
GPT-5.6 Luna$0.052Fits in one request

GPT-5.6 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-5.6 Luna
SpecificationGoogle Gemini 3.6 FlashOpenAI GPT-5.6 Luna
MakerGoogleOpenAI
WeightsNo public weights listedNo public weights listed
ReleasedJuly 21, 2026July 9, 2026
Context window1.05M1.05M
Input $/Mtok$0.75$0.20
Output $/Mtok$3.75$1.20
Coding index62.558.0
Independent measurements behind it46
Cost per solved task$1.49$0.04
SourceOpenRouter listingOpenRouter listing

Questions

Is Gemini 3.6 Flash better than GPT-5.6 Luna for coding?

Pick Gemini 3.6 Flash for coding: it scores 62.5 on the Vibe Coding Index against 58.0 for GPT-5.6 Luna, though on 4 benchmarks against 6. Pick GPT-5.6 Luna for output tokens 3.1x cheaper ($1.20 vs $3.75 per million) and a lower cost per solved task ($0.04 against $1.49).

Which is cheaper, Gemini 3.6 Flash or GPT-5.6 Luna?

Gemini 3.6 Flash costs $0.75 per million input tokens and $3.75 per million output tokens; GPT-5.6 Luna costs $0.20 and $1.20. Per solved SWE-bench Verified task, Gemini 3.6 Flash costs $1.49 and GPT-5.6 Luna $0.04.

Which has the bigger context window, Gemini 3.6 Flash or GPT-5.6 Luna?

GPT-5.6 Luna, with 1.05M tokens against 1.05M.

How many benchmarks is the Gemini 3.6 Flash vs GPT-5.6 Luna comparison based on?

100 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-5.6 Luna's on 6. Where only one model has a result, the page says so instead of naming a winner.

Compare next

Embed this comparison on your site

Free under CC BY 4.0, while the source link stays visible. Preview the frame · Terms and other embeds

<iframe src="https://llmbenchmark.ai/embed/compare/gemini-3-6-flash-vs-gpt-5-6-luna" title="Gemini 3.6 Flash vs GPT-5.6 Luna, LLMBenchmark.ai" width="100%" height="360" style="border:0;max-width:100%" loading="lazy"></iframe>
<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-5-6-luna">LLMBenchmark.ai, Gemini 3.6 Flash vs GPT-5.6 Luna</a></p>