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Gemini 3.7 Flash vs GPT-5.6 Luna

Updated October 21, 2026. 102 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.

Replace Gemini 3.7 Flash Replace GPT-5.6 Luna
Gemini 3.7 FlashGoogle
Coding
69.9
Overall
39.6
Output $/M
$3.75
80
GPT-5.6 LunaOpenAI
Coding
61.5
Overall
37.3
Output $/M
$1.20
21
vs boards won of 102 shared, 1 tied

Decision reading

Pick Gemini 3.7 Flash for coding: it scores 69.9 on the Vibe Coding Index against 61.5 for GPT-5.6 Luna.

Pick GPT-5.6 Luna when output tokens cost 3.1x less, or when a solved task costs $0.04 against $1.78.

Model AGemini 3.7 FlashGoogle69.9/1002 independent benchmarks$1.78 per solved taskModel BGPT-5.6 LunaOpenAI61.5/1002 independent benchmarks$0.04 per solved task
Shared results
102
Gemini 3.7 Flash only
10
GPT-5.6 Luna only
14
Like-for-like categories
8 of 9

Shared results can support a head-to-head reading. Results only one model has describe coverage, not superiority.

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 3.7 Flash 69.9 from 2 benchmarks, GPT-5.6 Luna 61.5 from 2 benchmarks.
Widest category
Web design, 11.5 points apart on average over 9 shared benchmarks.
Widest single gap
CyberBench (Vals AI): Gemini 3.7 Flash 43.8% against GPT-5.6 Luna 73.6%, 29.9 points apart on a 0 to 100 scale.
Output price
Gemini 3.7 Flash $3.75 against GPT-5.6 Luna $1.20 per million output tokens, 3.1x apart.
Context window
Gemini 3.7 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 3.7 FlashBarsGPT-5.6 LunaTies
Coding1361 tie
Intelligence20
Agentic work64
Reasoning150
Math24
Knowledge82
Web design81
General264
All shared boards80211 tie
CodingLike-for-likeFour of these boards feed the Vibe Coding Index136
Coding benchmarks for Gemini 3.7 Flash and GPT-5.6 Luna
BenchmarkGemini 3.7 FlashGPT-5.6 LunaLeader
LiveBench coding80.5%73.6%Gemini 3.7 Flash
LMArena WebDev15911518Gemini 3.7 Flash
AA Coding Index71.571.4Gemini 3.7 Flash
LiveCodeBench (Vals AI)88.7%Not measuredOnly Gemini 3.7 Flash measured
SWE-bench Verified (Vals AI)80.8%93.0%GPT-5.6 Luna
Terminal-Bench 4 (Vals AI)12.1%11.6%Gemini 3.7 Flash
Vibe Code Bench (Vals AI)70.4%77.1%GPT-5.6 Luna
Code migration (Vals AI)34.8%44.5%GPT-5.6 Luna
ProgramBench (Vals AI)0.0%0.0%Tie
IOI (Vals AI)67.8%61.8%Gemini 3.7 Flash
Terminal-Bench 2.1 (Vals AI)77.5%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)65.9%60.5%Gemini 3.7 Flash
CyberBench (Vals AI)43.8%73.6%GPT-5.6 Luna
SciCode59.8%53.6%Gemini 3.7 Flash
FrontierCode43.6%39.8%Gemini 3.7 Flash
FrontierSWE20.3%Not measuredOnly Gemini 3.7 Flash measured
WeirdMLNot measured60.9%Only GPT-5.6 Luna measured
ALE-Bench904.31667.4GPT-5.6 Luna
LMArena Text: coding14991466Gemini 3.7 Flash
LMArena Text: software and IT14981463Gemini 3.7 Flash
LMArena WebDev: React15871508Gemini 3.7 Flash
LMArena WebDev: HTML15931520Gemini 3.7 Flash
LMArena WebDev: from an image15991517Gemini 3.7 Flash
Neither model has a result on the other 14 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
Intelligence benchmarks for Gemini 3.7 Flash and GPT-5.6 Luna
BenchmarkGemini 3.7 FlashGPT-5.6 LunaLeader
AA Intelligence Index39.637.3Gemini 3.7 Flash
Epoch Capabilities Index158.0156.5Gemini 3.7 Flash
Agentic workLike-for-likePublic boards, shown as published, kept out of the index64
Agentic work benchmarks for Gemini 3.7 Flash and GPT-5.6 Luna
BenchmarkGemini 3.7 FlashGPT-5.6 LunaLeader
AA Agentic IndexNot measured42.1Only GPT-5.6 Luna measured
Design Arena: agents building web apps1224Not measuredOnly Gemini 3.7 Flash measured
Design Arena: agents building full-stack apps1208Not measuredOnly Gemini 3.7 Flash measured
Design Arena: agents building mobile apps1230Not measuredOnly Gemini 3.7 Flash measured
Design Arena: agents building Android apps1247Not measuredOnly Gemini 3.7 Flash measured
Design Arena: agents building Godot games1264Not measuredOnly Gemini 3.7 Flash measured
Design Arena: agents building games1235Not measuredOnly Gemini 3.7 Flash measured
Design Arena: spreadsheets1028Not measuredOnly Gemini 3.7 Flash measured
LiveBench research76.5%51.0%Gemini 3.7 Flash
LiveBench browser56.0%68.0%GPT-5.6 Luna
LiveBench long agentic28.3%30.4%GPT-5.6 Luna
SREBench (Vals AI)4.6%1.5%Gemini 3.7 Flash
Finance Agent (Vals AI)59.0%55.0%Gemini 3.7 Flash
Tax Agent Bench (Vals AI)22.8%24.8%GPT-5.6 Luna
Legal Research Bench (Vals AI)34.6%36.5%GPT-5.6 Luna
Excel Modeling Benchmark (Vals AI)71.3%67.1%Gemini 3.7 Flash
BioMysteryBench (Vals AI)Not measured61.5%Only GPT-5.6 Luna measured
Terminal-Bench-Science (Vals AI)7.1%0.0%Gemini 3.7 Flash
Vals Science IndexNot measured25.3%Only GPT-5.6 Luna measured
APEX-Agents67.8%43.0%Gemini 3.7 Flash
Remote Labor Index5.0%Not measuredOnly Gemini 3.7 Flash measured
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 16 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index150
Reasoning benchmarks for Gemini 3.7 Flash and GPT-5.6 Luna
BenchmarkGemini 3.7 FlashGPT-5.6 LunaLeader
GPQA Diamond93.9%91.7%Gemini 3.7 Flash
LiveBench reasoning87.8%85.6%Gemini 3.7 Flash
MysteryMechanism (Vals AI)Not measured14.4%Only GPT-5.6 Luna measured
MMMU Pro (Vals AI)89.0%85.0%Gemini 3.7 Flash
GPQA Diamond (Artificial Analysis run)94.5%91.1%Gemini 3.7 Flash
Humanity's Last Exam (Artificial Analysis run)47.9%39.5%Gemini 3.7 Flash
GPQA Diamond (Epoch AI run)94.8%91.6%Gemini 3.7 Flash
ARC-AGI95.5%88.0%Gemini 3.7 Flash
ARC-AGI-284.6%59.5%Gemini 3.7 Flash
SimpleBenchNot measured46.8%Only GPT-5.6 Luna measured
Chess puzzles66.0%43.0%Gemini 3.7 Flash
Mystery game puzzles37.0%21.0%Gemini 3.7 Flash
LMArena Text: hard prompts14951451Gemini 3.7 Flash
LMArena Text: expert15121478Gemini 3.7 Flash
LMArena Text: hard prompts in English14871460Gemini 3.7 Flash
LMArena Vision: diagrams13291273Gemini 3.7 Flash
LMArena Vision: homework13201282Gemini 3.7 Flash
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 3.7 Flash and GPT-5.6 Luna
BenchmarkGemini 3.7 FlashGPT-5.6 LunaLeader
OTIS Mock AIME97.2%98.3%GPT-5.6 Luna
FrontierMath, tiers 1 to 371.6%82.1%GPT-5.6 Luna
FrontierMath, tier 436.6%61.0%GPT-5.6 Luna
ProofBench58.0%60.0%GPT-5.6 Luna
LMArena Text: math15111459Gemini 3.7 Flash
LMArena Text: mathematical work15021470Gemini 3.7 Flash
Neither model has a result on the other 7 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index82
Knowledge benchmarks for Gemini 3.7 Flash and GPT-5.6 Luna
BenchmarkGemini 3.7 FlashGPT-5.6 LunaLeader
MMLU Pro90.1%86.0%Gemini 3.7 Flash
LegalBench (Vals AI)87.3%84.0%Gemini 3.7 Flash
CorpFin (Vals AI)Not measured64.2%Only GPT-5.6 Luna measured
TaxEval (Vals AI)74.7%76.2%GPT-5.6 Luna
MortgageTax (Vals AI)66.7%67.3%GPT-5.6 Luna
MedCode (Vals AI)53.4%42.4%Gemini 3.7 Flash
SimpleQA Verified69.2%41.0%Gemini 3.7 Flash
LMArena Text: science15111433Gemini 3.7 Flash
LMArena Text: medicine and healthcare14941399Gemini 3.7 Flash
LMArena Text: legal and government14961446Gemini 3.7 Flash
LMArena Text: business and finance14791439Gemini 3.7 Flash
Neither model has a result on the other 6 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index81
Web design benchmarks for Gemini 3.7 Flash and GPT-5.6 Luna
BenchmarkGemini 3.7 FlashGPT-5.6 LunaLeader
Design Arena: websites13041256Gemini 3.7 Flash
Design Arena: UI components12991250Gemini 3.7 Flash
Design Arena: game dev13181196Gemini 3.7 Flash
Design Arena: data viz13151212Gemini 3.7 Flash
Design Arena: 3D13081121Gemini 3.7 Flash
Design Arena: all code categories13081231Gemini 3.7 Flash
Design Arena: SVG12831193Gemini 3.7 Flash
Design Arena: ASCII art12761144Gemini 3.7 Flash
LiveBench design73.2%76.0%GPT-5.6 Luna
GeneralLike-for-likePublic boards, shown as published, kept out of the index264
General benchmarks for Gemini 3.7 Flash and GPT-5.6 Luna
BenchmarkGemini 3.7 FlashGPT-5.6 LunaLeader
LiveBench data analysis68.0%78.0%GPT-5.6 Luna
Public Benefits Bench (Vals AI)Not measured61.2%Only GPT-5.6 Luna measured
SAGE (Vals AI)49.2%44.2%Gemini 3.7 Flash
MedScribe (Vals AI)83.9%84.4%GPT-5.6 Luna
Vals Multimodal IndexNot measured69.1%Only GPT-5.6 Luna measured
Long context reasoning (AA-LCR)83.0%83.7%GPT-5.6 Luna
DTBench96.8%89.1%Gemini 3.7 Flash
LMCA50.4%48.5%Gemini 3.7 Flash
Surface Evolver BenchNot measured61.9%Only GPT-5.6 Luna measured
Furniture assembly26.7%42.5%GPT-5.6 Luna
LMArena Text14891431Gemini 3.7 Flash
LMArena Text: instruction following14841437Gemini 3.7 Flash
LMArena Text: creative writing14881396Gemini 3.7 Flash
LMArena Vision13141257Gemini 3.7 Flash
LMArena Text: English14831441Gemini 3.7 Flash
LMArena Text: non-English14871417Gemini 3.7 Flash
LMArena Text: Chinese15521470Gemini 3.7 Flash
LMArena Text: German15061455Gemini 3.7 Flash
LMArena Text: Japanese15111415Gemini 3.7 Flash
LMArena Text: Korean14811415Gemini 3.7 Flash
LMArena Text: French15001458Gemini 3.7 Flash
LMArena Text: Spanish14951446Gemini 3.7 Flash
LMArena Text: Russian15151427Gemini 3.7 Flash
LMArena Text: Polish15031405Gemini 3.7 Flash
LMArena Text: multi-turn14851434Gemini 3.7 Flash
LMArena Text: longer queries14921436Gemini 3.7 Flash
LMArena Text: writing and language14911419Gemini 3.7 Flash
LMArena Text: entertainment and media14771402Gemini 3.7 Flash
LMArena Vision: English13091263Gemini 3.7 Flash
LMArena Vision: Chinese13941294Gemini 3.7 Flash
LMArena Vision: reading text13221264Gemini 3.7 Flash
LMArena Vision: humor12991190Gemini 3.7 Flash
LMArena Vision: creative writing13121257Gemini 3.7 Flash
LMArena DocumentNot measured1457Only GPT-5.6 Luna measured
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 3.7 Flash and GPT-5.6 Luna
BenchmarkGemini 3.7 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 3.7 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 3.7 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 3.7 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 3.7 Flash and GPT-5.6 Luna
SpecificationGoogle Gemini 3.7 FlashOpenAI GPT-5.6 Luna
MakerGoogleOpenAI
WeightsNo public weights listedNo public weights listed
ReleasedAugust 13, 2026July 9, 2026
Context window1.05M1.05M
Input $/Mtok$0.75$0.20
Output $/Mtok$3.75$1.20
Coding index69.961.5
Independent measurements behind it22
Cost per solved task$1.78$0.04
SourceOpenRouter listingOpenRouter listing

Questions

Is Gemini 3.7 Flash better than GPT-5.6 Luna for coding?

Pick Gemini 3.7 Flash for coding: it scores 69.9 on the Vibe Coding Index against 61.5 for GPT-5.6 Luna. Pick GPT-5.6 Luna when output tokens cost 3.1x less, or when a solved task costs $0.04 against $1.78.

Which is cheaper, Gemini 3.7 Flash or GPT-5.6 Luna?

Gemini 3.7 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 3.7 Flash costs $1.78 and GPT-5.6 Luna $0.04.

Which has the bigger context window, Gemini 3.7 Flash or GPT-5.6 Luna?

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

How many benchmarks is the Gemini 3.7 Flash vs GPT-5.6 Luna comparison based on?

102 benchmarks have a result for both models as of October 21, 2026. Gemini 3.7 Flash's coding index rests on 2 independent benchmarks and GPT-5.6 Luna's on 2. 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-3-7-flash-vs-gpt-5-6-luna">LLMBenchmark.ai, Gemini 3.7 Flash vs GPT-5.6 Luna</a></p>