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Gemini 3.1 Flash Lite Preview vs GPT-6 Luna

GPT-6 Luna leads Gemini 3.1 Flash Lite Preview on coding, 57.3 to 22.7 on the Vibe Coding Index, and GPT-6 Luna costs 3.0x less per output token ($0.50 vs $1.50 per million). Updated October 22, 2026; 61 benchmarks have a result for both.

Replace Gemini 3.1 Flash Lite Preview Replace GPT-6 Luna
Gemini 3.1 Flash Lite PreviewGoogle
Coding
22.7
Overall
36.6
Output $/M
$1.50
29
GPT-6 LunaOpenAI
Coding
57.3
Overall
59.7
Output $/M
$0.50
32
vs boards won of 61 shared

Gemini 3.1 Flash Lite Preview or GPT-6 Luna: which to pick

Pick GPT-6 Luna for coding: it scores 57.3 on the Vibe Coding Index against 22.7 for Gemini 3.1 Flash Lite Preview.

Pick Gemini 3.1 Flash Lite Preview for work measured by LMArena Vision: homework or LMArena Text: math, where it leads.

Model AGemini 3.1 Flash Lite PreviewGoogle22.7/1003 independent benchmarks$0.18 per solved taskModel BGPT-6 LunaOpenAI57.3/1005 independent benchmarksNo cost per solved task
Shared results
61
Gemini 3.1 Flash Lite Preview only
18
GPT-6 Luna only
42
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 3.1 Flash Lite Preview 22.7 from 3 benchmarks, GPT-6 Luna 57.3 from 5 benchmarks.
Widest category
Coding, 35.1 points apart on average over 11 shared benchmarks.
Widest single gap
Vibe Code Bench (Vals AI): Gemini 3.1 Flash Lite Preview 0.0% against GPT-6 Luna 81.7%, 81.7 points apart on a 0 to 100 scale.
Output price
Gemini 3.1 Flash Lite Preview $1.50 against GPT-6 Luna $0.50 per million output tokens, 3.0x apart.
Context window
Gemini 3.1 Flash Lite Preview 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 3.1 Flash Lite PreviewBarsGPT-6 LunaTies
Coding011
Intelligence01
Agentic work04
Reasoning14
Math11
Knowledge51
Web design17
General213
All shared boards2932
CodingLike-for-likeSix of these boards feed the Vibe Coding Index011
Coding benchmarks for Gemini 3.1 Flash Lite Preview and GPT-6 Luna
BenchmarkGemini 3.1 Flash Lite PreviewGPT-6 LunaLeader
LiveBench codingNot measured84.5%Only GPT-6 Luna measured
LMArena WebDev12571578GPT-6 Luna
AA Coding Index34.7Not measuredOnly Gemini 3.1 Flash Lite Preview measured
LiveCodeBench (Vals AI)80.1%Not measuredOnly Gemini 3.1 Flash Lite Preview measured
SWE-bench Verified (Vals AI)62.8%Not measuredOnly Gemini 3.1 Flash Lite Preview measured
Terminal-Bench 4 (Vals AI)Not measured13.6%Only GPT-6 Luna measured
Vibe Code Bench (Vals AI)0.0%81.7%GPT-6 Luna
Code migration (Vals AI)4.6%42.5%GPT-6 Luna
ProgramBench (Vals AI)0.0%0.5%GPT-6 Luna
IOI (Vals AI)Not measured55.6%Only GPT-6 Luna measured
Terminal-Bench 2.1 (Vals AI)34.1%73.0%GPT-6 Luna
SWE-bench Multimodal (Vals AI)Not measured37.5%Only GPT-6 Luna measured
CyberBench (Vals AI)Not measured76.3%Only GPT-6 Luna measured
SciCodeNot measured54.6%Only GPT-6 Luna measured
FrontierCodeNot measured42.4%Only GPT-6 Luna measured
ALE-Bench797.71576.9GPT-6 Luna
LMArena Text: coding14001437GPT-6 Luna
LMArena Text: software and IT14131423GPT-6 Luna
LMArena WebDev: React12451573GPT-6 Luna
LMArena WebDev: HTML12761595GPT-6 Luna
LMArena WebDev: from an image13361571GPT-6 Luna
SciCode4.6%Not measuredOnly Gemini 3.1 Flash Lite Preview measured
Neither model has a result on the other 17 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index01
Intelligence benchmarks for Gemini 3.1 Flash Lite Preview and GPT-6 Luna
BenchmarkGemini 3.1 Flash Lite PreviewGPT-6 LunaLeader
AA Intelligence Index15.638.1GPT-6 Luna
Epoch Capabilities IndexNot measured156.8Only GPT-6 Luna measured
Agentic workLike-for-likePublic boards, shown as published, kept out of the index04
Agentic work benchmarks for Gemini 3.1 Flash Lite Preview and GPT-6 Luna
BenchmarkGemini 3.1 Flash Lite PreviewGPT-6 LunaLeader
AA Agentic Index1.6Not measuredOnly Gemini 3.1 Flash Lite Preview measured
Design Arena: agents building web appsNot measured1191Only GPT-6 Luna measured
Design Arena: agents building full-stack appsNot measured1158Only GPT-6 Luna measured
Design Arena: agents building mobile appsNot measured1134Only GPT-6 Luna 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)30.0%49.9%GPT-6 Luna
Tax Agent Bench (Vals AI)3.1%19.9%GPT-6 Luna
Legal Research Bench (Vals AI)3.4%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)8.6%68.5%GPT-6 Luna
BioMysteryBench (Vals AI)Not measured61.5%Only GPT-6 Luna measured
Terminal-Bench-Science (Vals AI)Not measured4.3%Only GPT-6 Luna measured
Vals Science IndexNot measured28.4%Only GPT-6 Luna measured
APEX-AgentsNot measured44.3%Only GPT-6 Luna measured
SpireClimbNot measured0.0%Only GPT-6 Luna measured
Neither model has a result on the other 23 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index14
Reasoning benchmarks for Gemini 3.1 Flash Lite Preview and GPT-6 Luna
BenchmarkGemini 3.1 Flash Lite PreviewGPT-6 LunaLeader
GPQA Diamond81.1%Not measuredOnly Gemini 3.1 Flash Lite Preview 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)82.5%Not measuredOnly Gemini 3.1 Flash Lite Preview measured
Humanity's Last Exam (Artificial Analysis run)Not measured38.5%Only GPT-6 Luna measured
GPQA Diamond (Epoch AI run)Not measured90.5%Only GPT-6 Luna measured
ARC-AGINot measured86.7%Only GPT-6 Luna measured
ARC-AGI-2Not measured59.3%Only GPT-6 Luna measured
Chess puzzlesNot measured36.0%Only GPT-6 Luna measured
Mystery game puzzlesNot measured7.0%Only GPT-6 Luna measured
LMArena Text: hard prompts14071410GPT-6 Luna
LMArena Text: expert13981442GPT-6 Luna
LMArena Text: hard prompts in English14031410GPT-6 Luna
LMArena Vision: diagrams12421245GPT-6 Luna
LMArena Vision: homework12711261Gemini 3.1 Flash Lite Preview
Neither model has a result on the other 7 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index11
Math benchmarks for Gemini 3.1 Flash Lite Preview and GPT-6 Luna
BenchmarkGemini 3.1 Flash Lite PreviewGPT-6 LunaLeader
AIME83.3%Not measuredOnly Gemini 3.1 Flash Lite Preview measured
OTIS Mock AIMENot measured98.9%Only GPT-6 Luna measured
FrontierMath, tiers 1 to 3Not measured78.9%Only GPT-6 Luna measured
FrontierMath, tier 4Not measured56.1%Only GPT-6 Luna measured
ProofBenchNot measured64.0%Only GPT-6 Luna measured
LMArena Text: math14281409Gemini 3.1 Flash Lite Preview
LMArena Text: mathematical work14171427GPT-6 Luna
Neither model has a result on the other 6 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index51
Knowledge benchmarks for Gemini 3.1 Flash Lite Preview and GPT-6 Luna
BenchmarkGemini 3.1 Flash Lite PreviewGPT-6 LunaLeader
MMLU Pro86.2%Not measuredOnly Gemini 3.1 Flash Lite Preview measured
LegalBench (Vals AI)83.8%Not measuredOnly Gemini 3.1 Flash Lite Preview measured
CaseLaw (Vals AI)55.0%Not measuredOnly Gemini 3.1 Flash Lite Preview measured
CorpFin (Vals AI)59.4%Not measuredOnly Gemini 3.1 Flash Lite Preview measured
TaxEval (Vals AI)71.8%Not measuredOnly Gemini 3.1 Flash Lite Preview measured
MortgageTax (Vals AI)68.0%Not measuredOnly Gemini 3.1 Flash Lite Preview measured
MedCode (Vals AI)47.6%44.7%Gemini 3.1 Flash Lite Preview
SimpleQA VerifiedNot measured41.4%Only GPT-6 Luna measured
LMArena Text: science14251386Gemini 3.1 Flash Lite Preview
LMArena Text: medicine and healthcare14281352Gemini 3.1 Flash Lite Preview
LMArena Text: legal and government14181400Gemini 3.1 Flash Lite Preview
LMArena Text: business and finance13891388Gemini 3.1 Flash Lite Preview
FACTS Benchmark Suite51.4%63.3%GPT-6 Luna
Neither model has a result on the other 5 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index17
Web design benchmarks for Gemini 3.1 Flash Lite Preview and GPT-6 Luna
BenchmarkGemini 3.1 Flash Lite PreviewGPT-6 LunaLeader
Design Arena: websites10821271GPT-6 Luna
Design Arena: UI components10691295GPT-6 Luna
Design Arena: game dev10291257GPT-6 Luna
Design Arena: data viz10451216GPT-6 Luna
Design Arena: 3D10471218GPT-6 Luna
Design Arena: all code categories10721270GPT-6 Luna
Design Arena: SVG10521252GPT-6 Luna
Design Arena: ASCII art11671153Gemini 3.1 Flash Lite Preview
LiveBench designNot measured82.5%Only GPT-6 Luna measured
GeneralLike-for-likePublic boards, shown as published, kept out of the index213
General benchmarks for Gemini 3.1 Flash Lite Preview and GPT-6 Luna
BenchmarkGemini 3.1 Flash Lite PreviewGPT-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)Not measured57.6%Only GPT-6 Luna measured
SAGE (Vals AI)49.5%48.1%Gemini 3.1 Flash Lite Preview
MedScribe (Vals AI)63.9%83.7%GPT-6 Luna
Vals Multimodal Index41.4%Not measuredOnly Gemini 3.1 Flash Lite Preview measured
Long context reasoning (AA-LCR)Not measured83.3%Only GPT-6 Luna measured
DTBenchNot measured90.1%Only GPT-6 Luna measured
LMCANot measured44.5%Only GPT-6 Luna measured
Furniture assemblyNot measured44.2%Only GPT-6 Luna measured
LMArena Text14161389Gemini 3.1 Flash Lite Preview
LMArena Text: instruction following13771408GPT-6 Luna
LMArena Text: creative writing14011363Gemini 3.1 Flash Lite Preview
LMArena Vision12401216Gemini 3.1 Flash Lite Preview
LMArena Text: English14141393Gemini 3.1 Flash Lite Preview
LMArena Text: non-English14101381Gemini 3.1 Flash Lite Preview
LMArena Text: Chinese14601427Gemini 3.1 Flash Lite Preview
LMArena Text: German14301376Gemini 3.1 Flash Lite Preview
LMArena Text: Japanese14131369Gemini 3.1 Flash Lite Preview
LMArena Text: Korean13921359Gemini 3.1 Flash Lite Preview
LMArena Text: French14241408Gemini 3.1 Flash Lite Preview
LMArena Text: Spanish14211391Gemini 3.1 Flash Lite Preview
LMArena Text: Russian14201392Gemini 3.1 Flash Lite Preview
LMArena Text: Polish14431383Gemini 3.1 Flash Lite Preview
LMArena Text: multi-turn14171392Gemini 3.1 Flash Lite Preview
LMArena Text: longer queries13941408GPT-6 Luna
LMArena Text: writing and language14081384Gemini 3.1 Flash Lite Preview
LMArena Text: entertainment and media13861364Gemini 3.1 Flash Lite Preview
LMArena Vision: English12321204Gemini 3.1 Flash Lite Preview
LMArena Vision: Chinese12781266Gemini 3.1 Flash Lite Preview
LMArena Vision: reading text12461225Gemini 3.1 Flash Lite Preview
LMArena Vision: humor1266Not measuredOnly Gemini 3.1 Flash Lite Preview measured
LMArena Vision: captioning1259Not measuredOnly Gemini 3.1 Flash Lite Preview measured
LMArena Vision: recognizing things1308Not measuredOnly Gemini 3.1 Flash Lite Preview measured
LMArena Vision: creative writing12481205Gemini 3.1 Flash Lite Preview
Neither model has a result on the other 11 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for Gemini 3.1 Flash Lite Preview and GPT-6 Luna
BenchmarkGemini 3.1 Flash Lite PreviewGPT-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 3.1 Flash Lite Preview$0.0010Fits in one request
GPT-6 Luna$0.0003Fits in one request

GPT-6 Luna costs less

Repository review

50K input + 3K output tokens

Gemini 3.1 Flash Lite Preview$0.017Fits in one request
GPT-6 Luna$0.0065Fits in one request

GPT-6 Luna costs less

Agent loop

200K input + 10K output tokens

Gemini 3.1 Flash Lite Preview$0.065Fits 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 3.1 Flash Lite Preview and GPT-6 Luna
SpecificationGoogle Gemini 3.1 Flash Lite PreviewOpenAI GPT-6 Luna
MakerGoogleOpenAI
WeightsNo public weights listedNo public weights listed
ReleasedMarch 3, 2026September 22, 2026
Context window1.05M1.05M
Input $/Mtok$0.25$0.10
Output $/Mtok$1.50$0.50
Coding index22.757.3
Independent measurements behind it35
Cost per solved task$0.18Not computable
SourceOpenRouter listingOpenRouter listing

Questions

Is Gemini 3.1 Flash Lite Preview better than GPT-6 Luna for coding?

Pick GPT-6 Luna for coding: it scores 57.3 on the Vibe Coding Index against 22.7 for Gemini 3.1 Flash Lite Preview. Pick Gemini 3.1 Flash Lite Preview for work measured by LMArena Vision: homework or LMArena Text: math, where it leads.

Which is cheaper, Gemini 3.1 Flash Lite Preview or GPT-6 Luna?

Gemini 3.1 Flash Lite Preview costs $0.25 per million input tokens and $1.50 per million output tokens; GPT-6 Luna costs $0.10 and $0.50. Cost per solved task is known for Gemini 3.1 Flash Lite Preview only.

Which has the bigger context window, Gemini 3.1 Flash Lite Preview or GPT-6 Luna?

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

How many benchmarks is the Gemini 3.1 Flash Lite Preview vs GPT-6 Luna comparison based on?

61 benchmarks have a result for both models as of October 22, 2026. Gemini 3.1 Flash Lite Preview's coding index rests on 3 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-3-1-flash-lite-preview-vs-gpt-6-luna">LLMBenchmark.ai, Gemini 3.1 Flash Lite Preview vs GPT-6 Luna</a></p>