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GPT-5.6 Luna vs Inkling

GPT-5.6 Luna leads Inkling on coding, 58.0 to 31.5 on the Vibe Coding Index, and GPT-5.6 Luna costs 3.4x less per output token ($1.20 vs $4.05 per million). Updated October 22, 2026; 97 benchmarks have a result for both.

Replace GPT-5.6 Luna Replace Inkling
GPT-5.6 LunaOpenAI
Coding
58.0
Overall
61.6
Output $/M
$1.20
76
T InklingThinking Machines
Coding
31.5
Overall
46.5
Output $/M
$4.05
20
vs boards won of 97 shared, 1 tied

GPT-5.6 Luna or Inkling: which to pick

Pick GPT-5.6 Luna for coding: it scores 58.0 on the Vibe Coding Index against 31.5 for Inkling.

Pick Inkling for work measured by LMArena Text: software and IT or LiveBench research, where it leads.

Model AGPT-5.6 LunaOpenAI58.0/1006 independent benchmarks$0.04 per solved taskModel BInklingThinking Machines31.5/1006 independent benchmarks$0.76 per solved task
Shared results
97
GPT-5.6 Luna only
22
Inkling only
5
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
GPT-5.6 Luna 58.0 from 6 benchmarks, Inkling 31.5 from 6 benchmarks.
Widest category
Math, 29.9 points apart on average over 6 shared benchmarks.
Widest single gap
ProofBench: GPT-5.6 Luna 60.0% against Inkling 0.0%, 60.0 points apart on a 0 to 100 scale.
Output price
GPT-5.6 Luna $1.20 against Inkling $4.05 per million output tokens, 3.4x apart.
Context window
GPT-5.6 Luna takes 1.05M tokens, Inkling 524K.

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
CategoryGPT-5.6 LunaBarsInklingTies
Coding1911 tie
Intelligence20
Agentic work91
Reasoning121
Math51
Knowledge65
Web design81
General1510
All shared boards76201 tie
CodingLike-for-likeSix of these boards feed the Vibe Coding Index191
Coding benchmarks for GPT-5.6 Luna and Inkling
BenchmarkGPT-5.6 LunaInklingLeader
LiveBench coding73.6%64.0%GPT-5.6 Luna
LMArena WebDev15181414GPT-5.6 Luna
AA Coding Index71.452.1GPT-5.6 Luna
LiveCodeBench (Vals AI)Not measured85.5%Only Inkling measured
SWE-bench Verified (Vals AI)93.0%77.6%GPT-5.6 Luna
Terminal-Bench 4 (Vals AI)11.6%0.5%GPT-5.6 Luna
Vibe Code Bench (Vals AI)77.1%19.2%GPT-5.6 Luna
Code migration (Vals AI)44.5%11.8%GPT-5.6 Luna
ProgramBench (Vals AI)0.0%0.0%Tie
IOI (Vals AI)61.8%14.9%GPT-5.6 Luna
Terminal-Bench 2.1 (Vals AI)79.0%47.6%GPT-5.6 Luna
Vibe Code Bench 1-100 (Vals AI)22.6%7.3%GPT-5.6 Luna
SkillsBench (Vals AI)60.5%26.1%GPT-5.6 Luna
CyberBench (Vals AI)73.6%66.8%GPT-5.6 Luna
SciCode53.6%47.0%GPT-5.6 Luna
FrontierCode39.8%14.0%GPT-5.6 Luna
FrontierSWENot measured4.1%Only Inkling measured
WeirdML60.9%32.3%GPT-5.6 Luna
ALE-Bench1667.4946.0GPT-5.6 Luna
LMArena Text: coding14661466GPT-5.6 Luna
LMArena Text: software and IT14631465Inkling
LMArena WebDev: React15081404GPT-5.6 Luna
LMArena WebDev: HTML15201399GPT-5.6 Luna
LMArena WebDev: from an image1517Not measuredOnly GPT-5.6 Luna measured
SciCode6.2%Not measuredOnly GPT-5.6 Luna measured
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 GPT-5.6 Luna and Inkling
BenchmarkGPT-5.6 LunaInklingLeader
AA Intelligence Index37.325.0GPT-5.6 Luna
Epoch Capabilities Index156.5148.4GPT-5.6 Luna
Agentic workLike-for-likePublic boards, shown as published, kept out of the index91
Agentic work benchmarks for GPT-5.6 Luna and Inkling
BenchmarkGPT-5.6 LunaInklingLeader
AA Agentic Index42.122.5GPT-5.6 Luna
Design Arena: agents building web appsNot measured1196Only Inkling measured
LiveBench research51.0%59.9%Inkling
LiveBench browser68.0%16.0%GPT-5.6 Luna
LiveBench long agentic30.4%14.1%GPT-5.6 Luna
SREBench (Vals AI)1.5%0.0%GPT-5.6 Luna
Finance Agent (Vals AI)55.0%46.6%GPT-5.6 Luna
Tax Agent Bench (Vals AI)24.8%15.3%GPT-5.6 Luna
Legal Research Bench (Vals AI)36.5%28.4%GPT-5.6 Luna
Harvey's Legal Agent Benchmark (Vals AI)Not measured3.8%Only Inkling measured
Excel Modeling Benchmark (Vals AI)67.1%38.4%GPT-5.6 Luna
BioMysteryBench (Vals AI)61.5%Not measuredOnly GPT-5.6 Luna measured
Terminal-Bench-Science (Vals AI)0.0%Not measuredOnly GPT-5.6 Luna measured
Vals Science Index25.3%Not measuredOnly GPT-5.6 Luna measured
APEX-Agents43.0%33.8%GPT-5.6 Luna
BALROG45.6%Not measuredOnly GPT-5.6 Luna measured
Vending-Bench 2$4,095Not measuredOnly GPT-5.6 Luna measured
Neither model has a result on the other 24 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index121
Reasoning benchmarks for GPT-5.6 Luna and Inkling
BenchmarkGPT-5.6 LunaInklingLeader
GPQA Diamond91.7%87.1%GPT-5.6 Luna
LiveBench reasoning85.6%78.3%GPT-5.6 Luna
MysteryMechanism (Vals AI)14.4%Not measuredOnly GPT-5.6 Luna measured
MMMU Pro (Vals AI)85.0%78.5%GPT-5.6 Luna
GPQA Diamond (Artificial Analysis run)91.1%87.2%GPT-5.6 Luna
Humanity's Last Exam (Artificial Analysis run)39.5%31.9%GPT-5.6 Luna
GPQA Diamond (Epoch AI run)91.6%88.3%GPT-5.6 Luna
ARC-AGI88.0%79.5%GPT-5.6 Luna
ARC-AGI-259.5%36.5%GPT-5.6 Luna
SimpleBench46.8%50.0%Inkling
Chess puzzles43.0%21.0%GPT-5.6 Luna
Mystery game puzzles21.0%Not measuredOnly GPT-5.6 Luna measured
LMArena Text: hard prompts14511451GPT-5.6 Luna
LMArena Text: expert14781466GPT-5.6 Luna
LMArena Text: hard prompts in English14601448GPT-5.6 Luna
LMArena Vision: diagrams1273Not measuredOnly GPT-5.6 Luna measured
LMArena Vision: homework1282Not measuredOnly GPT-5.6 Luna measured
Kagi LLM Benchmark49.1%Not measuredOnly 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 index51
Math benchmarks for GPT-5.6 Luna and Inkling
BenchmarkGPT-5.6 LunaInklingLeader
OTIS Mock AIME98.3%88.9%GPT-5.6 Luna
FrontierMath, tiers 1 to 382.1%33.3%GPT-5.6 Luna
FrontierMath, tier 461.0%4.9%GPT-5.6 Luna
ProofBench60.0%0.0%GPT-5.6 Luna
LMArena Text: math14591479Inkling
LMArena Text: mathematical work14701460GPT-5.6 Luna
Neither model has a result on the other 7 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index65
Knowledge benchmarks for GPT-5.6 Luna and Inkling
BenchmarkGPT-5.6 LunaInklingLeader
MMLU Pro86.0%86.3%Inkling
LegalBench (Vals AI)84.0%83.0%GPT-5.6 Luna
CorpFin (Vals AI)64.2%68.6%Inkling
TaxEval (Vals AI)76.2%75.3%GPT-5.6 Luna
MortgageTax (Vals AI)67.3%64.0%GPT-5.6 Luna
MedCode (Vals AI)42.4%41.2%GPT-5.6 Luna
SimpleQA Verified41.0%40.3%GPT-5.6 Luna
LMArena Text: science14331455Inkling
LMArena Text: medicine and healthcare13991447Inkling
LMArena Text: legal and government14461448Inkling
LMArena Text: business and finance14391438GPT-5.6 Luna
FACTS Benchmark Suite35.0%Not measuredOnly GPT-5.6 Luna measured
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 GPT-5.6 Luna and Inkling
BenchmarkGPT-5.6 LunaInklingLeader
Design Arena: websites12551224GPT-5.6 Luna
Design Arena: UI components12481198GPT-5.6 Luna
Design Arena: game dev11941165GPT-5.6 Luna
Design Arena: data viz12111156GPT-5.6 Luna
Design Arena: 3D11211160Inkling
Design Arena: all code categories12311205GPT-5.6 Luna
Design Arena: SVG11941108GPT-5.6 Luna
Design Arena: ASCII art11421089GPT-5.6 Luna
LiveBench design76.0%58.3%GPT-5.6 Luna
GeneralLike-for-likePublic boards, shown as published, kept out of the index1510
General benchmarks for GPT-5.6 Luna and Inkling
BenchmarkGPT-5.6 LunaInklingLeader
Vals IndexNot measured29.0%Only Inkling measured
LiveBench data analysis78.0%72.8%GPT-5.6 Luna
Public Benefits Bench (Vals AI)61.2%58.5%GPT-5.6 Luna
SAGE (Vals AI)44.2%36.5%GPT-5.6 Luna
MedScribe (Vals AI)84.4%85.4%Inkling
Vals Multimodal Index69.1%49.4%GPT-5.6 Luna
Long context reasoning (AA-LCR)83.7%77.3%GPT-5.6 Luna
DTBench89.1%87.5%GPT-5.6 Luna
LMCA48.5%37.6%GPT-5.6 Luna
Surface Evolver Bench61.9%Not measuredOnly GPT-5.6 Luna measured
Furniture assembly42.5%Not measuredOnly GPT-5.6 Luna measured
LMArena Text14311442Inkling
LMArena Text: instruction following14371425GPT-5.6 Luna
LMArena Text: creative writing13961390GPT-5.6 Luna
LMArena Vision1257Not measuredOnly GPT-5.6 Luna measured
LMArena Text: English14411442Inkling
LMArena Text: non-English14171434Inkling
LMArena Text: Chinese14701493Inkling
LMArena Text: German14551445GPT-5.6 Luna
LMArena Text: Japanese14151429Inkling
LMArena Text: Korean14151403GPT-5.6 Luna
LMArena Text: French14581455GPT-5.6 Luna
LMArena Text: Spanish14461449Inkling
LMArena Text: Russian14271430Inkling
LMArena Text: Polish14051450Inkling
LMArena Text: multi-turn14341437Inkling
LMArena Text: longer queries14361435GPT-5.6 Luna
LMArena Text: writing and language14191404GPT-5.6 Luna
LMArena Text: entertainment and media14021394GPT-5.6 Luna
LMArena Vision: English1263Not measuredOnly GPT-5.6 Luna measured
LMArena Vision: Chinese1294Not measuredOnly GPT-5.6 Luna measured
LMArena Vision: reading text1264Not measuredOnly GPT-5.6 Luna measured
LMArena Vision: humor1190Not measuredOnly GPT-5.6 Luna measured
LMArena Vision: creative writing1257Not measuredOnly GPT-5.6 Luna measured
LMArena Document1457Not measuredOnly GPT-5.6 Luna measured
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 GPT-5.6 Luna and Inkling
BenchmarkGPT-5.6 LunaInklingLeader
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

GPT-5.6 Luna$0.0008Fits in one request
Inkling$0.0030Fits in one request

GPT-5.6 Luna costs less

Repository review

50K input + 3K output tokens

GPT-5.6 Luna$0.014Fits in one request
Inkling$0.061Fits in one request

GPT-5.6 Luna costs less

Agent loop

200K input + 10K output tokens

GPT-5.6 Luna$0.052Fits in one request
Inkling$0.235Fits 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 GPT-5.6 Luna and Inkling
SpecificationOpenAI GPT-5.6 LunaThinking Machines Inkling
MakerOpenAIThinking Machines
WeightsNo public weights listedOpen weights
ReleasedJuly 9, 2026July 17, 2026
Context window1.05M524K
Input $/Mtok$0.20$0.975
Output $/Mtok$1.20$4.05
Coding index58.031.5
Independent measurements behind it66
Cost per solved task$0.04$0.76
SourceOpenRouter listingOpenRouter listing

Questions

Is GPT-5.6 Luna better than Inkling for coding?

Pick GPT-5.6 Luna for coding: it scores 58.0 on the Vibe Coding Index against 31.5 for Inkling. Pick Inkling for work measured by LMArena Text: software and IT or LiveBench research, where it leads.

Which is cheaper, GPT-5.6 Luna or Inkling?

GPT-5.6 Luna costs $0.20 per million input tokens and $1.20 per million output tokens; Inkling costs $0.975 and $4.05. Per solved SWE-bench Verified task, GPT-5.6 Luna costs $0.04 and Inkling $0.76.

Which has the bigger context window, GPT-5.6 Luna or Inkling?

GPT-5.6 Luna, with 1.05M tokens against 524K.

How many benchmarks is the GPT-5.6 Luna vs Inkling comparison based on?

97 benchmarks have a result for both models as of October 22, 2026. GPT-5.6 Luna's coding index rests on 6 independent benchmarks and Inkling's on 6. 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/gpt-5-6-luna-vs-thinkingmachines-inkling">LLMBenchmark.ai, GPT-5.6 Luna vs Inkling</a></p>