Gemini 4 Carbon vs GPT-5.6 Luna

Gemini 4 Carbon leads GPT-5.6 Luna on coding, 86.6 to 55.3 on the Vibe Coding Index, and GPT-5.6 Luna costs 8.3x less per output token ($1.20 vs $10.00 per million). Updated November 14, 2026; 58 benchmarks have a result for both.

Replace Gemini 4 Carbon Replace GPT-5.6 Luna

Gemini 4 CarbonGoogle

Coding: 86.6
Overall: 88.3
Output $/M: $10.00

GPT-5.6 LunaOpenAI

Coding: 55.3
Overall: 57.1
Output $/M: $1.20

vs boards won of 58 shared

Gemini 4 Carbon or GPT-5.6 Luna: which to pick

Pick Gemini 4 Carbon for coding: it scores 86.6 on the Vibe Coding Index against 55.3 for GPT-5.6 Luna, though on 4 benchmarks against 5.

Pick GPT-5.6 Luna for output tokens 8.3x cheaper ($1.20 vs $10.00 per million) and a larger context window (1.05M against 1.05M tokens).

Model AGemini 4 CarbonGoogle86.6/1004 independent benchmarksNo cost per solved task Model BGPT-5.6 LunaOpenAI55.3/1005 independent benchmarks$0.04 per solved task

581567

Shared results: 58
Gemini 4 Carbon only: 15
GPT-5.6 Luna only: 67
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
Gemini 4 Carbon
Gemini 4 Carbon scores 86.6 against 55.3.
4 and 5 benchmarks behind the scores
Intelligence
AA Intelligence Index
Gemini 4 Carbon
Gemini 4 Carbon leads, 60.0 against 23.8.
Same board, both measured
Agentic work
AA Agentic Index
No call
Only GPT-5.6 Luna has a AA Agentic Index result, 42.1.
Directional only
Reasoning
GPQA Diamond
No call
Only GPT-5.6 Luna has a GPQA Diamond result, 91.7%.
Directional only
Knowledge
MMLU Pro
No call
Only GPT-5.6 Luna has a MMLU Pro result, 86.0%.
Directional only
Web design
Design Arena: websites
Gemini 4 Carbon
Gemini 4 Carbon leads, 1319 against 1248.
Same board, both measured
General
Vals Index
No call
Only Gemini 4 Carbon has a Vals Index result, 70.5%.
Directional only
Long documents
Listed context window
GPT-5.6 Luna
GPT-5.6 Luna takes 1.05M tokens against 1.05M.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
GPT-5.6 Luna
Gemini 4 Carbon $0.0070, GPT-5.6 Luna $0.0008 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only GPT-5.6 Luna has the number, $0.04.
Directional only

At a glance

Coding index: Gemini 4 Carbon 86.6 from 4 benchmarks, GPT-5.6 Luna 55.3 from 5 benchmarks.
Widest category: Agentic work, 40.4 points apart on average over 4 shared benchmarks.
Widest single gap: Vending-Bench 2: Gemini 4 Carbon $16,484 against GPT-5.6 Luna $4,095, 74.4 points apart on a 0 to 100 scale.
Output price: Gemini 4 Carbon $10.00 against GPT-5.6 Luna $1.20 per million output tokens, 8.3x apart.
Context window: Gemini 4 Carbon 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
Category	Gemini 4 Carbon	GPT-5.6 Luna
Coding	11	0
Intelligence	2	0
Agentic work	4	0
Reasoning	11	0
Math	4	0
Knowledge	7	0
Web design	5	0
General	13	1
All shared boards	57	1

CodingLike-for-likeSix of these boards feed the Vibe Coding Index110

Coding benchmarks for Gemini 4 Carbon and GPT-5.6 Luna
Benchmark	Gemini 4 Carbon	GPT-5.6 Luna	Leader
LiveBench coding	91.0%	Not measured	Only Gemini 4 Carbon measured
LMArena WebDev	1768	1519	Gemini 4 Carbon
AA Coding Index	Not measured	71.4	Only GPT-5.6 Luna measured
SWE-bench Verified (Vals AI)	Not measured	93.0%	Only GPT-5.6 Luna measured
Terminal-Bench 4 (Vals AI)	63.1%	11.6%	Gemini 4 Carbon
Vibe Code Bench (Vals AI)	89.1%	77.1%	Gemini 4 Carbon
Code migration (Vals AI)	Not measured	44.5%	Only GPT-5.6 Luna measured
ProgramBench (Vals AI)	Not measured	0.0%	Only GPT-5.6 Luna measured
IOI (Vals AI)	Not measured	61.8%	Only GPT-5.6 Luna measured
Terminal-Bench 2.1 (Vals AI)	Not measured	79.0%	Only GPT-5.6 Luna measured
Vibe Code Bench 1-100 (Vals AI)	Not measured	22.6%	Only GPT-5.6 Luna measured
SkillsBench (Vals AI)	Not measured	60.5%	Only GPT-5.6 Luna measured
CyberBench (Vals AI)	Not measured	73.6%	Only GPT-5.6 Luna measured
SciCode	Not measured	53.6%	Only GPT-5.6 Luna measured
Terminal-Bench 4.0 (Artificial Analysis run)	65.2%	11.6%	Gemini 4 Carbon
FrontierCode 2.0	40.6%	17.6%	Gemini 4 Carbon
FrontierCode	Not measured	39.8%	Only GPT-5.6 Luna measured
FrontierSWE	61.2%	Not measured	Only Gemini 4 Carbon measured
WeirdML	Not measured	60.9%	Only GPT-5.6 Luna measured
MirrorCode	Not measured	21.1%	Only GPT-5.6 Luna measured
ALE-Bench	2374.7	1667.4	Gemini 4 Carbon
LMArena Text: coding	1564	1467	Gemini 4 Carbon
LMArena Text: software and IT	1552	1464	Gemini 4 Carbon
LMArena WebDev: React	1792	1508	Gemini 4 Carbon
LMArena WebDev: HTML	1770	1522	Gemini 4 Carbon
LMArena WebDev: from an image	Not measured	1517	Only GPT-5.6 Luna measured
SciCode	Not measured	6.2%	Only GPT-5.6 Luna measured
GameBench 2	Not measured	54.0	Only GPT-5.6 Luna measured
Terminal-Bench 2.1	Not measured	75.7%	Only GPT-5.6 Luna measured
Terminal-Bench 3.0	Not measured	14.3%	Only GPT-5.6 Luna measured
Terminal-Bench 4.0	Not measured	17.3%	Only GPT-5.6 Luna measured
CursorBench 4.0	60.4%	35.9%	Gemini 4 Carbon
Neither model has a result on the other 20 boards here

IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20

Intelligence benchmarks for Gemini 4 Carbon and GPT-5.6 Luna
Benchmark	Gemini 4 Carbon	GPT-5.6 Luna	Leader
AA Intelligence Index	60.0	23.8	Gemini 4 Carbon
Epoch Capabilities Index	169.8	156.7	Gemini 4 Carbon

Agentic workLike-for-likePublic boards, shown as published, kept out of the index40

Agentic work benchmarks for Gemini 4 Carbon and GPT-5.6 Luna
Benchmark	Gemini 4 Carbon	GPT-5.6 Luna	Leader
AA Agentic Index	Not measured	42.1	Only GPT-5.6 Luna measured
Design Arena: agents building mobile apps	1284	Not measured	Only Gemini 4 Carbon measured
Design Arena: spreadsheets	1224	Not measured	Only Gemini 4 Carbon measured
LiveBench research	92.5%	Not measured	Only Gemini 4 Carbon measured
LiveBench browser	80.0%	Not measured	Only Gemini 4 Carbon measured
LiveBench long agentic	72.7%	Not measured	Only Gemini 4 Carbon measured
SREBench (Vals AI)	Not measured	1.5%	Only GPT-5.6 Luna measured
Finance Agent (Vals AI)	Not measured	55.0%	Only GPT-5.6 Luna measured
Tax Agent Bench (Vals AI)	51.8%	24.8%	Gemini 4 Carbon
Legal Research Bench (Vals AI)	55.8%	36.5%	Gemini 4 Carbon
Harvey's Legal Agent Benchmark (Vals AI)	17.5%	Not measured	Only Gemini 4 Carbon measured
Excel Modeling Benchmark (Vals AI)	Not measured	67.1%	Only GPT-5.6 Luna measured
BioMysteryBench (Vals AI)	Not measured	61.5%	Only GPT-5.6 Luna measured
Terminal-Bench-Science (Vals AI)	Not measured	0.0%	Only GPT-5.6 Luna measured
Vals Science Index	Not measured	25.3%	Only GPT-5.6 Luna measured
APEX-Agents	84.2%	43.0%	Gemini 4 Carbon
BALROG	Not measured	45.6%	Only GPT-5.6 Luna measured
Vending-Bench 2	$16,484	$4,095	Gemini 4 Carbon
Neither model has a result on the other 26 boards here

ReasoningLike-for-likePublic boards, shown as published, kept out of the index110

Reasoning benchmarks for Gemini 4 Carbon and GPT-5.6 Luna
Benchmark	Gemini 4 Carbon	GPT-5.6 Luna	Leader
GPQA Diamond	Not measured	91.7%	Only GPT-5.6 Luna measured
LiveBench reasoning	90.6%	Not measured	Only Gemini 4 Carbon measured
MysteryMechanism (Vals AI)	Not measured	14.4%	Only GPT-5.6 Luna measured
MMMU Pro (Vals AI)	Not measured	85.0%	Only GPT-5.6 Luna measured
GPQA Diamond (Artificial Analysis run)	Not measured	91.1%	Only GPT-5.6 Luna measured
Humanity's Last Exam (Artificial Analysis run)	Not measured	39.5%	Only GPT-5.6 Luna measured
HLE-Diamond (Artificial Analysis run)	69.1%	20.9%	Gemini 4 Carbon
CritPt v2, hard subset (Artificial Analysis run)	69.0%	30.5%	Gemini 4 Carbon
GPQA Diamond (Epoch AI run)	96.5%	91.6%	Gemini 4 Carbon
ARC-AGI	98.5%	88.0%	Gemini 4 Carbon
ARC-AGI-2	94.2%	59.5%	Gemini 4 Carbon
SimpleBench	92.6%	46.8%	Gemini 4 Carbon
Chess puzzles	78.0%	43.0%	Gemini 4 Carbon
Mystery game puzzles	73.0%	21.0%	Gemini 4 Carbon
EBR-bench	87.6%	Not measured	Only Gemini 4 Carbon measured
LMArena Text: hard prompts	1551	1452	Gemini 4 Carbon
LMArena Text: expert	1582	1477	Gemini 4 Carbon
LMArena Text: hard prompts in English	1545	1460	Gemini 4 Carbon
LMArena Vision: diagrams	Not measured	1271	Only GPT-5.6 Luna measured
LMArena Vision: homework	Not measured	1281	Only GPT-5.6 Luna measured
Kagi LLM Benchmark	Not measured	49.1%	Only GPT-5.6 Luna measured
GoBench	Not measured	1091	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 index40

Math benchmarks for Gemini 4 Carbon and GPT-5.6 Luna
Benchmark	Gemini 4 Carbon	GPT-5.6 Luna	Leader
OTIS Mock AIME	100.0%	98.3%	Gemini 4 Carbon
FrontierMath, tiers 1 to 3	90.5%	82.1%	Gemini 4 Carbon
FrontierMath, tier 4	95.1%	61.0%	Gemini 4 Carbon
ProofBench	Not measured	60.0%	Only GPT-5.6 Luna measured
LMArena Text: math	Not measured	1457	Only GPT-5.6 Luna measured
LMArena Text: mathematical work	1538	1467	Gemini 4 Carbon
MathArena	85.4%	Not measured	Only Gemini 4 Carbon 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 4 Carbon and GPT-5.6 Luna
Benchmark	Gemini 4 Carbon	GPT-5.6 Luna	Leader
MMLU Pro	Not measured	86.0%	Only GPT-5.6 Luna measured
LegalBench (Vals AI)	Not measured	84.0%	Only GPT-5.6 Luna measured
CorpFin (Vals AI)	Not measured	64.2%	Only GPT-5.6 Luna measured
TaxEval (Vals AI)	Not measured	76.2%	Only GPT-5.6 Luna measured
MortgageTax (Vals AI)	Not measured	67.3%	Only GPT-5.6 Luna measured
MedCode (Vals AI)	Not measured	42.4%	Only GPT-5.6 Luna measured
AA-Omniscience	53.5	-17.1	Gemini 4 Carbon
SimpleQA Verified	77.7%	41.0%	Gemini 4 Carbon
LMArena Text: science	1535	1434	Gemini 4 Carbon
LMArena Text: medicine and healthcare	1525	1399	Gemini 4 Carbon
LMArena Text: legal and government	1542	1444	Gemini 4 Carbon
LMArena Text: business and finance	1520	1439	Gemini 4 Carbon
FACTS Benchmark Suite	78.4%	56.9%	Gemini 4 Carbon
PRBench Legal	53.3%	Not measured	Only Gemini 4 Carbon measured
Neither model has a result on the other 7 boards here

Web designLike-for-likePublic boards, shown as published, kept out of the index50

Web design benchmarks for Gemini 4 Carbon and GPT-5.6 Luna
Benchmark	Gemini 4 Carbon	GPT-5.6 Luna	Leader
Design Arena: websites	1319	1248	Gemini 4 Carbon
Design Arena: UI components	1357	1241	Gemini 4 Carbon
Design Arena: game dev	1326	1190	Gemini 4 Carbon
Design Arena: data viz	Not measured	1203	Only GPT-5.6 Luna measured
Design Arena: 3D	1434	1099	Gemini 4 Carbon
Design Arena: all code categories	1348	1221	Gemini 4 Carbon
Design Arena: SVG	Not measured	1185	Only GPT-5.6 Luna measured
Design Arena: ASCII art	Not measured	1142	Only GPT-5.6 Luna measured
LiveBench design	80.2%	Not measured	Only Gemini 4 Carbon measured

GeneralLike-for-likePublic boards, shown as published, kept out of the index131

General benchmarks for Gemini 4 Carbon and GPT-5.6 Luna
Benchmark	Gemini 4 Carbon	GPT-5.6 Luna	Leader
Vals Index	70.5%	Not measured	Only Gemini 4 Carbon measured
LiveBench data analysis	86.5%	Not measured	Only Gemini 4 Carbon measured
Public Benefits Bench (Vals AI)	Not measured	61.2%	Only GPT-5.6 Luna measured
MedScribe (Vals AI)	Not measured	84.4%	Only GPT-5.6 Luna measured
Vals Multimodal Index	Not measured	69.1%	Only GPT-5.6 Luna measured
Long context reasoning (AA-LCR)	79.3%	83.7%	GPT-5.6 Luna
GDPval-AA	1733	1470	Gemini 4 Carbon
DTBench	Not measured	89.1%	Only GPT-5.6 Luna measured
LMCA	Not measured	48.5%	Only GPT-5.6 Luna measured
Surface Evolver Bench	Not measured	61.9%	Only GPT-5.6 Luna measured
Furniture assembly	77.5%	42.5%	Gemini 4 Carbon
LMArena Text	1538	1431	Gemini 4 Carbon
LMArena Text: instruction following	1539	1437	Gemini 4 Carbon
LMArena Text: creative writing	1533	1396	Gemini 4 Carbon
LMArena Vision	Not measured	1256	Only GPT-5.6 Luna measured
LMArena Text: English	1530	1442	Gemini 4 Carbon
LMArena Text: non-English	1534	1417	Gemini 4 Carbon
LMArena Text: Chinese	1613	1472	Gemini 4 Carbon
LMArena Text: German	Not measured	1456	Only GPT-5.6 Luna measured
LMArena Text: Japanese	Not measured	1416	Only GPT-5.6 Luna measured
LMArena Text: Korean	Not measured	1408	Only GPT-5.6 Luna measured
LMArena Text: French	Not measured	1454	Only GPT-5.6 Luna measured
LMArena Text: Spanish	Not measured	1448	Only GPT-5.6 Luna measured
LMArena Text: Russian	1560	1426	Gemini 4 Carbon
LMArena Text: Polish	Not measured	1403	Only GPT-5.6 Luna measured
LMArena Text: multi-turn	1569	1434	Gemini 4 Carbon
LMArena Text: longer queries	1549	1436	Gemini 4 Carbon
LMArena Text: writing and language	1542	1418	Gemini 4 Carbon
LMArena Text: entertainment and media	1527	1401	Gemini 4 Carbon
LMArena Vision: English	Not measured	1260	Only GPT-5.6 Luna measured
LMArena Vision: Chinese	Not measured	1301	Only GPT-5.6 Luna measured
LMArena Vision: reading text	Not measured	1263	Only GPT-5.6 Luna measured
LMArena Vision: humor	Not measured	1192	Only GPT-5.6 Luna measured
LMArena Vision: creative writing	Not measured	1256	Only GPT-5.6 Luna measured
LMArena Document	Not measured	1454	Only GPT-5.6 Luna measured
EQ-Bench 4	Not measured	1146	Only GPT-5.6 Luna measured
Neither model has a result on the other 13 boards here

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

Image generation benchmarks for Gemini 4 Carbon and GPT-5.6 Luna
Benchmark	Gemini 4 Carbon	GPT-5.6 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 4 Carbon$0.0070Fits 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 4 Carbon$0.130Fits 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 4 Carbon$0.500Fits 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 4 Carbon and GPT-5.6 Luna
Specification	Google Gemini 4 Carbon	OpenAI GPT-5.6 Luna
Maker	Google	OpenAI
Weights	No public weights listed	No public weights listed
Released	November 10, 2026	July 9, 2026
Context window	1.05M	1.05M
Input $/Mtok	$2.00	$0.20
Output $/Mtok	$10.00	$1.20
Coding index	86.6	55.3
Independent measurements behind it	4	5
Cost per solved task	Not computable	$0.04
Source	OpenRouter listing	OpenRouter listing

Questions

Is Gemini 4 Carbon better than GPT-5.6 Luna for coding?

Pick Gemini 4 Carbon for coding: it scores 86.6 on the Vibe Coding Index against 55.3 for GPT-5.6 Luna, though on 4 benchmarks against 5. Pick GPT-5.6 Luna for output tokens 8.3x cheaper ($1.20 vs $10.00 per million) and a larger context window (1.05M against 1.05M tokens).

Which is cheaper, Gemini 4 Carbon or GPT-5.6 Luna?

Gemini 4 Carbon costs $2.00 per million input tokens and $10.00 per million output tokens; GPT-5.6 Luna costs $0.20 and $1.20. Cost per solved task is known for GPT-5.6 Luna only.

Which has the bigger context window, Gemini 4 Carbon or GPT-5.6 Luna?

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

How many benchmarks is the Gemini 4 Carbon vs GPT-5.6 Luna comparison based on?

58 benchmarks have a result for both models as of November 14, 2026. Gemini 4 Carbon's coding index rests on 4 independent benchmarks and GPT-5.6 Luna's on 5. Where only one model has a result, the page says so instead of naming a winner.

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Gemini 4 Carbon or GPT-5.6 Luna: which to pick

Which one for your work

Coding

Intelligence

Agentic work

Reasoning

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