Gemini 3.1 Pro Preview vs GPT-6 Luna

GPT-6 Luna leads Gemini 3.1 Pro Preview on coding, 57.3 to 32.3 on the Vibe Coding Index, and GPT-6 Luna costs 24.0x less per output token ($0.50 vs $12.00 per million). Updated October 22, 2026; 89 benchmarks have a result for both.

Replace Gemini 3.1 Pro Preview Replace GPT-6 Luna

Gemini 3.1 Pro PreviewGoogle

Coding: 32.3
Overall: 54.0
Output $/M: $12.00

GPT-6 LunaOpenAI

Coding: 57.3
Overall: 59.7
Output $/M: $0.50

vs boards won of 89 shared

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

Pick GPT-6 Luna for coding: it scores 57.3 on the Vibe Coding Index against 32.3 for Gemini 3.1 Pro Preview.

Pick Gemini 3.1 Pro Preview for work measured by SciCode or LMArena Text: coding, where it leads.

Model AGemini 3.1 Pro PreviewGoogle32.3/1004 independent benchmarks$0.99 per solved task Model BGPT-6 LunaOpenAI57.3/1005 independent benchmarksNo cost per solved task

894414

Shared results: 89
Gemini 3.1 Pro Preview only: 44
GPT-6 Luna only: 14
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.

Coding
Vibe Coding Index, six public coding benchmarks
GPT-6 Luna
GPT-6 Luna scores 57.3 against 32.3.
4 and 5 benchmarks behind the scores
Intelligence
AA Intelligence Index
GPT-6 Luna
GPT-6 Luna leads, 38.1 against 29.7.
Same board, both measured
Agentic work
AA Agentic Index
No call
Only Gemini 3.1 Pro Preview has a AA Agentic Index result, 8.2.
Directional only
Reasoning
GPQA Diamond
No call
Only Gemini 3.1 Pro Preview has a GPQA Diamond result, 95.5%.
Directional only
Math
AIME
No call
Only Gemini 3.1 Pro Preview has a AIME result, 98.1%.
Directional only
Knowledge
MMLU Pro
No call
Only Gemini 3.1 Pro Preview has a MMLU Pro result, 91.0%.
Directional only
Web design
Design Arena: websites
GPT-6 Luna
GPT-6 Luna leads, 1271 against 1233.
Same board, both measured
General
Vals Index
No call
Only GPT-6 Luna has a Vals Index result, 52.3%.
Directional only
Long documents
Listed context window
GPT-6 Luna
GPT-6 Luna takes 1.05M tokens against 1.05M.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
GPT-6 Luna
Gemini 3.1 Pro Preview $0.0080, GPT-6 Luna $0.0003 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Gemini 3.1 Pro Preview has the number, $0.99.
Directional only

At a glance

Coding index: Gemini 3.1 Pro Preview 32.3 from 4 benchmarks, GPT-6 Luna 57.3 from 5 benchmarks.
Widest category: Math, 18.5 points apart on average over 6 shared benchmarks.
Widest single gap: Vibe Code Bench (Vals AI): Gemini 3.1 Pro Preview 32.0% against GPT-6 Luna 81.7%, 49.6 points apart on a 0 to 100 scale.
Output price: Gemini 3.1 Pro Preview $12.00 against GPT-6 Luna $0.50 per million output tokens, 24.0x apart.
Context window: Gemini 3.1 Pro 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
Category	Gemini 3.1 Pro Preview	GPT-6 Luna
Coding	3	11
Intelligence	0	1
Agentic work	0	12
Reasoning	12	0
Math	2	4
Knowledge	7	0
Web design	3	5
General	25	4
All shared boards	52	37

CodingLike-for-likeSix of these boards feed the Vibe Coding Index311

Coding benchmarks for Gemini 3.1 Pro Preview and GPT-6 Luna
Benchmark	Gemini 3.1 Pro Preview	GPT-6 Luna	Leader
LiveBench coding	Not measured	84.5%	Only GPT-6 Luna measured
LMArena WebDev	1447	1578	GPT-6 Luna
AA Coding Index	68.8	Not measured	Only Gemini 3.1 Pro Preview measured
LiveCodeBench (Vals AI)	88.5%	Not measured	Only Gemini 3.1 Pro Preview measured
SWE-bench Verified (Vals AI)	78.8%	Not measured	Only Gemini 3.1 Pro Preview measured
Terminal-Bench 4 (Vals AI)	2.5%	13.6%	GPT-6 Luna
Vibe Code Bench (Vals AI)	32.0%	81.7%	GPT-6 Luna
Code migration (Vals AI)	17.3%	42.5%	GPT-6 Luna
ProgramBench (Vals AI)	0.0%	0.5%	GPT-6 Luna
IOI (Vals AI)	51.8%	55.6%	GPT-6 Luna
Terminal-Bench 2.1 (Vals AI)	70.8%	73.0%	GPT-6 Luna
SWE-bench Multimodal (Vals AI)	Not measured	37.5%	Only GPT-6 Luna measured
Vibe Code Bench 1-100 (Vals AI)	6.7%	Not measured	Only Gemini 3.1 Pro Preview measured
CyberBench (Vals AI)	Not measured	76.3%	Only GPT-6 Luna measured
SciCode	58.7%	54.6%	Gemini 3.1 Pro Preview
Terminal-Bench Hard (Artificial Analysis run)	53.8%	Not measured	Only Gemini 3.1 Pro Preview measured
Terminal-Bench	80.2%	Not measured	Only Gemini 3.1 Pro Preview measured
FrontierCode	Not measured	42.4%	Only GPT-6 Luna measured
GSO-Bench	22.6%	Not measured	Only Gemini 3.1 Pro Preview measured
WeirdML	72.1%	Not measured	Only Gemini 3.1 Pro Preview measured
MirrorCode	8.9%	Not measured	Only Gemini 3.1 Pro Preview measured
ALE-Bench	1160.6	1576.9	GPT-6 Luna
LMArena Text: coding	1484	1437	Gemini 3.1 Pro Preview
LMArena Text: software and IT	1487	1423	Gemini 3.1 Pro Preview
LMArena WebDev: React	1438	1573	GPT-6 Luna
LMArena WebDev: HTML	1490	1595	GPT-6 Luna
LMArena WebDev: from an image	1481	1571	GPT-6 Luna
SciCode	14.3%	Not measured	Only Gemini 3.1 Pro Preview measured
Neither model has a result on the other 11 boards here

IntelligenceLike-for-likePublic boards, shown as published, kept out of the index01

Intelligence benchmarks for Gemini 3.1 Pro Preview and GPT-6 Luna
Benchmark	Gemini 3.1 Pro Preview	GPT-6 Luna	Leader
AA Intelligence Index	29.7	38.1	GPT-6 Luna
Epoch Capabilities Index	Not measured	156.8	Only GPT-6 Luna measured

Agentic workLike-for-likePublic boards, shown as published, kept out of the index012

Agentic work benchmarks for Gemini 3.1 Pro Preview and GPT-6 Luna
Benchmark	Gemini 3.1 Pro Preview	GPT-6 Luna	Leader
AA Agentic Index	8.2	Not measured	Only Gemini 3.1 Pro Preview measured
Design Arena: agents building web apps	1125	1191	GPT-6 Luna
Design Arena: agents building full-stack apps	1068	1158	GPT-6 Luna
Design Arena: agents building mobile apps	1094	1134	GPT-6 Luna
Design Arena: agents building Android apps	1049	Not measured	Only Gemini 3.1 Pro Preview measured
Design Arena: agents building Godot games	1236	Not measured	Only Gemini 3.1 Pro Preview measured
Design Arena: agents building games	1113	Not measured	Only Gemini 3.1 Pro Preview measured
Design Arena: HTML slides	1103	Not measured	Only Gemini 3.1 Pro Preview measured
Design Arena: PowerPoint slides	1041	Not measured	Only Gemini 3.1 Pro Preview measured
LiveBench research	Not measured	43.5%	Only GPT-6 Luna measured
LiveBench browser	Not measured	72.0%	Only GPT-6 Luna measured
LiveBench long agentic	Not measured	48.1%	Only GPT-6 Luna measured
SREBench (Vals AI)	0.0%	2.7%	GPT-6 Luna
Finance Agent (Vals AI)	43.0%	49.9%	GPT-6 Luna
Tax Agent Bench (Vals AI)	9.3%	19.9%	GPT-6 Luna
Legal Research Bench (Vals AI)	20.7%	30.3%	GPT-6 Luna
Harvey's Legal Agent Benchmark (Vals AI)	Not measured	4.2%	Only GPT-6 Luna measured
Excel Modeling Benchmark (Vals AI)	52.6%	68.5%	GPT-6 Luna
BioMysteryBench (Vals AI)	60.0%	61.5%	GPT-6 Luna
Terminal-Bench-Science (Vals AI)	1.4%	4.3%	GPT-6 Luna
Vals Science Index	27.4%	28.4%	GPT-6 Luna
τ²-Bench Telecom	95.6%	Not measured	Only Gemini 3.1 Pro Preview measured
APEX-Agents	35.1%	44.3%	GPT-6 Luna
METR time horizons	77.0%	Not measured	Only Gemini 3.1 Pro Preview measured
BALROG	57.0%	Not measured	Only Gemini 3.1 Pro Preview measured
DeepResearch Bench	47.8%	Not measured	Only Gemini 3.1 Pro Preview measured
PostTrainBench	22.0%	Not measured	Only Gemini 3.1 Pro Preview measured
SpireClimb	Not measured	0.0%	Only GPT-6 Luna measured
Vending-Bench 2	$911	Not measured	Only Gemini 3.1 Pro Preview measured
Neither model has a result on the other 12 boards here

ReasoningLike-for-likePublic boards, shown as published, kept out of the index120

Reasoning benchmarks for Gemini 3.1 Pro Preview and GPT-6 Luna
Benchmark	Gemini 3.1 Pro Preview	GPT-6 Luna	Leader
GPQA Diamond	95.5%	Not measured	Only Gemini 3.1 Pro Preview measured
LiveBench reasoning	Not measured	81.8%	Only GPT-6 Luna measured
MysteryMechanism (Vals AI)	20.7%	19.4%	Gemini 3.1 Pro Preview
MMMU Pro (Vals AI)	88.2%	Not measured	Only Gemini 3.1 Pro Preview measured
GPQA Diamond (Artificial Analysis run)	94.1%	Not measured	Only Gemini 3.1 Pro Preview measured
Humanity's Last Exam (Artificial Analysis run)	47.0%	38.5%	Gemini 3.1 Pro Preview
GPQA Diamond (Epoch AI run)	94.4%	90.5%	Gemini 3.1 Pro Preview
ARC-AGI	98.0%	86.7%	Gemini 3.1 Pro Preview
ARC-AGI-2	77.1%	59.3%	Gemini 3.1 Pro Preview
SimpleBench	79.6%	Not measured	Only Gemini 3.1 Pro Preview measured
Chess puzzles	51.0%	36.0%	Gemini 3.1 Pro Preview
Mystery game puzzles	34.0%	7.0%	Gemini 3.1 Pro Preview
EBR-bench	14.3%	Not measured	Only Gemini 3.1 Pro Preview measured
LMArena Text: hard prompts	1485	1410	Gemini 3.1 Pro Preview
LMArena Text: expert	1483	1442	Gemini 3.1 Pro Preview
LMArena Text: hard prompts in English	1480	1410	Gemini 3.1 Pro Preview
LMArena Vision: diagrams	1311	1245	Gemini 3.1 Pro Preview
LMArena Vision: homework	1316	1261	Gemini 3.1 Pro Preview
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 3.1 Pro Preview and GPT-6 Luna
Benchmark	Gemini 3.1 Pro Preview	GPT-6 Luna	Leader
AIME	98.1%	Not measured	Only Gemini 3.1 Pro Preview measured
OTIS Mock AIME	95.6%	98.9%	GPT-6 Luna
FrontierMath, tiers 1 to 3	59.6%	78.9%	GPT-6 Luna
FrontierMath, tier 4	26.8%	56.1%	GPT-6 Luna
ProofBench	26.0%	64.0%	GPT-6 Luna
LMArena Text: math	1486	1409	Gemini 3.1 Pro Preview
LMArena Text: mathematical work	1478	1427	Gemini 3.1 Pro Preview
Neither model has a result on the other 6 boards here

KnowledgeLike-for-likePublic boards, shown as published, kept out of the index70

Knowledge benchmarks for Gemini 3.1 Pro Preview and GPT-6 Luna
Benchmark	Gemini 3.1 Pro Preview	GPT-6 Luna	Leader
MMLU Pro	91.0%	Not measured	Only Gemini 3.1 Pro Preview measured
LegalBench (Vals AI)	87.4%	Not measured	Only Gemini 3.1 Pro Preview measured
CaseLaw (Vals AI)	64.8%	Not measured	Only Gemini 3.1 Pro Preview measured
CorpFin (Vals AI)	64.5%	Not measured	Only Gemini 3.1 Pro Preview measured
TaxEval (Vals AI)	72.9%	Not measured	Only Gemini 3.1 Pro Preview measured
MortgageTax (Vals AI)	69.4%	Not measured	Only Gemini 3.1 Pro Preview measured
MedQA (Vals AI)	96.4%	Not measured	Only Gemini 3.1 Pro Preview measured
MedCode (Vals AI)	59.1%	44.7%	Gemini 3.1 Pro Preview
SimpleQA Verified	73.5%	41.4%	Gemini 3.1 Pro Preview
LMArena Text: science	1497	1386	Gemini 3.1 Pro Preview
LMArena Text: medicine and healthcare	1486	1352	Gemini 3.1 Pro Preview
LMArena Text: legal and government	1487	1400	Gemini 3.1 Pro Preview
LMArena Text: business and finance	1459	1388	Gemini 3.1 Pro Preview
FACTS Benchmark Suite	67.4%	63.3%	Gemini 3.1 Pro Preview
Neither model has a result on the other 4 boards here

Web designLike-for-likePublic boards, shown as published, kept out of the index35

Web design benchmarks for Gemini 3.1 Pro Preview and GPT-6 Luna
Benchmark	Gemini 3.1 Pro Preview	GPT-6 Luna	Leader
Design Arena: websites	1233	1271	GPT-6 Luna
Design Arena: UI components	1224	1295	GPT-6 Luna
Design Arena: game dev	1202	1257	GPT-6 Luna
Design Arena: data viz	1209	1216	GPT-6 Luna
Design Arena: 3D	1234	1218	Gemini 3.1 Pro Preview
Design Arena: all code categories	1231	1270	GPT-6 Luna
Design Arena: SVG	1285	1252	Gemini 3.1 Pro Preview
Design Arena: ASCII art	1270	1153	Gemini 3.1 Pro Preview
LiveBench design	Not measured	82.5%	Only GPT-6 Luna measured

GeneralLike-for-likePublic boards, shown as published, kept out of the index254

General benchmarks for Gemini 3.1 Pro Preview and GPT-6 Luna
Benchmark	Gemini 3.1 Pro Preview	GPT-6 Luna	Leader
Vals Index	Not measured	52.3%	Only GPT-6 Luna measured
LiveBench data analysis	Not measured	73.4%	Only GPT-6 Luna measured
Public Benefits Bench (Vals AI)	53.8%	57.6%	GPT-6 Luna
SAGE (Vals AI)	48.7%	48.1%	Gemini 3.1 Pro Preview
MedScribe (Vals AI)	76.1%	83.7%	GPT-6 Luna
Vals Multimodal Index	56.1%	Not measured	Only Gemini 3.1 Pro Preview measured
IFBench	77.1%	Not measured	Only Gemini 3.1 Pro Preview measured
Long context reasoning (AA-LCR)	82.0%	83.3%	GPT-6 Luna
DTBench	97.1%	90.1%	Gemini 3.1 Pro Preview
LMCA	53.8%	44.5%	Gemini 3.1 Pro Preview
CL-bench	20.8%	Not measured	Only Gemini 3.1 Pro Preview measured
Furniture assembly	26.7%	44.2%	GPT-6 Luna
ExploitBench	26.1%	Not measured	Only Gemini 3.1 Pro Preview measured
CL-bench Life	16.9%	Not measured	Only Gemini 3.1 Pro Preview measured
LMArena Text	1480	1389	Gemini 3.1 Pro Preview
LMArena Text: instruction following	1466	1408	Gemini 3.1 Pro Preview
LMArena Text: creative writing	1482	1363	Gemini 3.1 Pro Preview
LMArena Vision	1296	1216	Gemini 3.1 Pro Preview
LMArena Text: English	1478	1393	Gemini 3.1 Pro Preview
LMArena Text: non-English	1476	1381	Gemini 3.1 Pro Preview
LMArena Text: Chinese	1527	1427	Gemini 3.1 Pro Preview
LMArena Text: German	1490	1376	Gemini 3.1 Pro Preview
LMArena Text: Japanese	1491	1369	Gemini 3.1 Pro Preview
LMArena Text: Korean	1455	1359	Gemini 3.1 Pro Preview
LMArena Text: French	1487	1408	Gemini 3.1 Pro Preview
LMArena Text: Spanish	1481	1391	Gemini 3.1 Pro Preview
LMArena Text: Russian	1497	1392	Gemini 3.1 Pro Preview
LMArena Text: Polish	1498	1383	Gemini 3.1 Pro Preview
LMArena Text: multi-turn	1487	1392	Gemini 3.1 Pro Preview
LMArena Text: longer queries	1482	1408	Gemini 3.1 Pro Preview
LMArena Text: writing and language	1481	1384	Gemini 3.1 Pro Preview
LMArena Text: entertainment and media	1465	1364	Gemini 3.1 Pro Preview
LMArena Vision: English	1287	1204	Gemini 3.1 Pro Preview
LMArena Vision: Chinese	1364	1266	Gemini 3.1 Pro Preview
LMArena Vision: reading text	1304	1225	Gemini 3.1 Pro Preview
LMArena Vision: humor	1322	Not measured	Only Gemini 3.1 Pro Preview measured
LMArena Vision: captioning	1345	Not measured	Only Gemini 3.1 Pro Preview measured
LMArena Vision: recognizing things	1330	Not measured	Only Gemini 3.1 Pro Preview measured
LMArena Vision: creative writing	1324	1205	Gemini 3.1 Pro Preview
LMArena Document	1444	Not measured	Only Gemini 3.1 Pro Preview measured
Neither model has a result on the other 6 boards here

Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared

Image generation benchmarks for Gemini 3.1 Pro Preview and GPT-6 Luna
Benchmark	Gemini 3.1 Pro Preview	GPT-6 Luna	Leader
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 Pro Preview$0.0080Fits 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 Pro Preview$0.136Fits 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 Pro Preview$0.520Fits 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 Pro Preview and GPT-6 Luna
Specification	Google Gemini 3.1 Pro Preview	OpenAI GPT-6 Luna
Maker	Google	OpenAI
Weights	No public weights listed	No public weights listed
Released	February 19, 2026	September 22, 2026
Context window	1.05M	1.05M
Input $/Mtok	$2.00	$0.10
Output $/Mtok	$12.00	$0.50
Coding index	32.3	57.3
Independent measurements behind it	4	5
Cost per solved task	$0.99	Not computable
Source	OpenRouter listing	OpenRouter listing

Questions

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

Pick GPT-6 Luna for coding: it scores 57.3 on the Vibe Coding Index against 32.3 for Gemini 3.1 Pro Preview. Pick Gemini 3.1 Pro Preview for work measured by SciCode or LMArena Text: coding, where it leads.

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

Gemini 3.1 Pro Preview costs $2.00 per million input tokens and $12.00 per million output tokens; GPT-6 Luna costs $0.10 and $0.50. Cost per solved task is known for Gemini 3.1 Pro Preview only.

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

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

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

89 benchmarks have a result for both models as of October 22, 2026. Gemini 3.1 Pro Preview'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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<iframe src="https://llmbenchmark.ai/embed/compare/gemini-3-1-pro-preview-vs-gpt-6-luna" title="Gemini 3.1 Pro Preview vs GPT-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-3-1-pro-preview-vs-gpt-6-luna">LLMBenchmark.ai, Gemini 3.1 Pro Preview vs GPT-6 Luna</a></p>

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

Which one for your work

Coding

Intelligence

Agentic work

Reasoning

Math

Knowledge

Web design

General

Long documents

Everyday cost

Cost per solved task

At a glance

Benchmark by benchmark

What each workload costs

Chat turn

Repository review

Agent loop

Specification differences

Questions

Compare next