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Claude Opus 4.6 vs GPT-5.6 Luna

GPT-5.6 Luna leads Claude Opus 4.6 on coding, 58.0 to 57.2 on the Vibe Coding Index, and GPT-5.6 Luna costs 20.8x less per output token ($1.20 vs $25.00 per million). Updated October 22, 2026; 86 benchmarks have a result for both.

Replace Claude Opus 4.6 Replace GPT-5.6 Luna
Claude Opus 4.6Anthropic
Coding
57.2
Overall
66.0
Output $/M
$25.00
69
GPT-5.6 LunaOpenAI
Coding
58.0
Overall
61.6
Output $/M
$1.20
17
vs boards won of 86 shared

Claude Opus 4.6 or GPT-5.6 Luna: which to pick

Claude Opus 4.6 and GPT-5.6 Luna are level for coding, 57.2 against 58.0 on the Vibe Coding Index, so price and context decide.

Pick Claude Opus 4.6 for work measured by LMArena WebDev or WeirdML, where it leads. Pick GPT-5.6 Luna for output tokens 20.8x cheaper ($1.20 vs $25.00 per million) and a lower cost per solved task ($0.04 against $1.56).

Model AClaude Opus 4.6Anthropic57.2/1004 independent benchmarks$1.56 per solved taskModel BGPT-5.6 LunaOpenAI58.0/1006 independent benchmarks$0.04 per solved task
Shared results
86
Claude Opus 4.6 only
24
GPT-5.6 Luna only
33
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
Claude Opus 4.6 57.2 from 4 benchmarks, GPT-5.6 Luna 58.0 from 6 benchmarks.
Widest category
Agentic work, 13.9 points apart on average over 2 shared benchmarks.
Widest single gap
Kagi LLM Benchmark: Claude Opus 4.6 83.6% against GPT-5.6 Luna 49.1%, 34.5 points apart on a 0 to 100 scale.
Output price
Claude Opus 4.6 $25.00 against GPT-5.6 Luna $1.20 per million output tokens, 20.8x apart.
Context window
Claude Opus 4.6 takes 1M 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
CategoryClaude Opus 4.6BarsGPT-5.6 LunaTies
Coding73
Intelligence02
Agentic work20
Reasoning115
Math24
Knowledge111
Web design80
General282
All shared boards6917
CodingLike-for-likeSix of these boards feed the Vibe Coding Index73
Coding benchmarks for Claude Opus 4.6 and GPT-5.6 Luna
BenchmarkClaude Opus 4.6GPT-5.6 LunaLeader
SWE-bench Verified75.6%Not measuredOnly Claude Opus 4.6 measured
SWE-bench Multilingual72.0%Not measuredOnly Claude Opus 4.6 measured
LiveBench codingNot measured73.6%Only GPT-5.6 Luna measured
LMArena WebDev15471518Claude Opus 4.6
AA Coding IndexNot measured71.4Only GPT-5.6 Luna measured
LiveCodeBench (Vals AI)84.7%Not measuredOnly Claude Opus 4.6 measured
SWE-bench Verified (Vals AI)78.2%93.0%GPT-5.6 Luna
Terminal-Bench 4 (Vals AI)Not measured11.6%Only GPT-5.6 Luna measured
Vibe Code Bench (Vals AI)57.6%77.1%GPT-5.6 Luna
Code migration (Vals AI)Not measured44.5%Only GPT-5.6 Luna measured
ProgramBench (Vals AI)Not measured0.0%Only GPT-5.6 Luna measured
IOI (Vals AI)Not measured61.8%Only GPT-5.6 Luna measured
Terminal-Bench 2.1 (Vals AI)Not measured79.0%Only GPT-5.6 Luna measured
Vibe Code Bench 1-100 (Vals AI)Not measured22.6%Only GPT-5.6 Luna measured
SkillsBench (Vals AI)Not measured60.5%Only GPT-5.6 Luna measured
CyberBench (Vals AI)Not measured73.6%Only GPT-5.6 Luna measured
SciCodeNot measured53.6%Only GPT-5.6 Luna measured
Terminal-Bench Hard (Artificial Analysis run)48.5%Not measuredOnly Claude Opus 4.6 measured
Terminal-Bench79.8%Not measuredOnly Claude Opus 4.6 measured
FrontierCode26.6%39.8%GPT-5.6 Luna
GSO-Bench41.2%Not measuredOnly Claude Opus 4.6 measured
WeirdML78.0%60.9%Claude Opus 4.6
Cybench93.0%Not measuredOnly Claude Opus 4.6 measured
ALE-BenchNot measured1667.4Only GPT-5.6 Luna measured
LMArena Text: coding15341466Claude Opus 4.6
LMArena Text: software and IT15271463Claude Opus 4.6
LMArena WebDev: React15391508Claude Opus 4.6
LMArena WebDev: HTML15591520Claude Opus 4.6
LMArena WebDev: from an image15431517Claude Opus 4.6
SciCodeNot measured6.2%Only GPT-5.6 Luna measured
Neither model has a result on the other 9 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02
Intelligence benchmarks for Claude Opus 4.6 and GPT-5.6 Luna
BenchmarkClaude Opus 4.6GPT-5.6 LunaLeader
AA Intelligence Index31.937.3GPT-5.6 Luna
Epoch Capabilities Index155.7156.5GPT-5.6 Luna
Agentic workLike-for-likePublic boards, shown as published, kept out of the index20
Agentic work benchmarks for Claude Opus 4.6 and GPT-5.6 Luna
BenchmarkClaude Opus 4.6GPT-5.6 LunaLeader
AA Agentic IndexNot measured42.1Only GPT-5.6 Luna measured
Design Arena: agents building web apps1206Not measuredOnly Claude Opus 4.6 measured
Design Arena: agents building full-stack apps1220Not measuredOnly Claude Opus 4.6 measured
Design Arena: agents building mobile apps1207Not measuredOnly Claude Opus 4.6 measured
Design Arena: agents building Android apps1197Not measuredOnly Claude Opus 4.6 measured
Design Arena: agents building games1212Not measuredOnly Claude Opus 4.6 measured
LiveBench researchNot measured51.0%Only GPT-5.6 Luna measured
LiveBench browserNot measured68.0%Only GPT-5.6 Luna measured
LiveBench long agenticNot measured30.4%Only GPT-5.6 Luna measured
SREBench (Vals AI)Not measured1.5%Only GPT-5.6 Luna measured
Finance Agent (Vals AI)Not measured55.0%Only GPT-5.6 Luna measured
Tax Agent Bench (Vals AI)Not measured24.8%Only GPT-5.6 Luna measured
Legal Research Bench (Vals AI)Not measured36.5%Only GPT-5.6 Luna measured
Excel Modeling Benchmark (Vals AI)Not measured67.1%Only GPT-5.6 Luna measured
BioMysteryBench (Vals AI)Not measured61.5%Only GPT-5.6 Luna measured
Terminal-Bench-Science (Vals AI)Not measured0.0%Only GPT-5.6 Luna measured
Vals Science IndexNot measured25.3%Only GPT-5.6 Luna measured
τ²-Bench Telecom92.1%Not measuredOnly Claude Opus 4.6 measured
APEX-Agents46.3%43.0%Claude Opus 4.6
METR time horizons78.9%Not measuredOnly Claude Opus 4.6 measured
Remote Labor Index4.2%Not measuredOnly Claude Opus 4.6 measured
BALROGNot measured45.6%Only GPT-5.6 Luna measured
DeepResearch Bench55.3%Not measuredOnly Claude Opus 4.6 measured
Vending-Bench 2$8,018$4,095Claude Opus 4.6
Neither model has a result on the other 17 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index115
Reasoning benchmarks for Claude Opus 4.6 and GPT-5.6 Luna
BenchmarkClaude Opus 4.6GPT-5.6 LunaLeader
GPQA Diamond89.7%91.7%GPT-5.6 Luna
LiveBench reasoningNot measured85.6%Only GPT-5.6 Luna measured
MysteryMechanism (Vals AI)Not measured14.4%Only GPT-5.6 Luna measured
MMMU Pro (Vals AI)83.9%85.0%GPT-5.6 Luna
GPQA Diamond (Artificial Analysis run)89.6%91.1%GPT-5.6 Luna
Humanity's Last Exam (Artificial Analysis run)39.9%39.5%Claude Opus 4.6
GPQA Diamond (Epoch AI run)90.5%91.6%GPT-5.6 Luna
ARC-AGI94.0%88.0%Claude Opus 4.6
ARC-AGI-269.2%59.5%Claude Opus 4.6
SimpleBench67.6%46.8%Claude Opus 4.6
Chess puzzles21.0%43.0%GPT-5.6 Luna
Mystery game puzzles25.0%21.0%Claude Opus 4.6
EBR-bench12.7%Not measuredOnly Claude Opus 4.6 measured
LMArena Text: hard prompts15251451Claude Opus 4.6
LMArena Text: expert15441478Claude Opus 4.6
LMArena Text: hard prompts in English15301460Claude Opus 4.6
LMArena Vision: diagrams13401273Claude Opus 4.6
LMArena Vision: homework13371282Claude Opus 4.6
Kagi LLM Benchmark83.6%49.1%Claude Opus 4.6
Neither model has a result on the other 3 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index24
Math benchmarks for Claude Opus 4.6 and GPT-5.6 Luna
BenchmarkClaude Opus 4.6GPT-5.6 LunaLeader
AIME95.6%Not measuredOnly Claude Opus 4.6 measured
OTIS Mock AIME94.4%98.3%GPT-5.6 Luna
FrontierMath, tiers 1 to 366.0%82.1%GPT-5.6 Luna
FrontierMath, tier 426.8%61.0%GPT-5.6 Luna
ProofBench50.0%60.0%GPT-5.6 Luna
LMArena Text: math15181459Claude Opus 4.6
LMArena Text: mathematical work15251470Claude Opus 4.6
Neither model has a result on the other 6 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index111
Knowledge benchmarks for Claude Opus 4.6 and GPT-5.6 Luna
BenchmarkClaude Opus 4.6GPT-5.6 LunaLeader
MMLU Pro89.1%86.0%Claude Opus 4.6
LegalBench (Vals AI)85.3%84.0%Claude Opus 4.6
CaseLaw (Vals AI)62.1%Not measuredOnly Claude Opus 4.6 measured
CorpFin (Vals AI)67.0%64.2%Claude Opus 4.6
TaxEval (Vals AI)76.0%76.2%GPT-5.6 Luna
MortgageTax (Vals AI)68.5%67.3%Claude Opus 4.6
MedQA (Vals AI)95.4%Not measuredOnly Claude Opus 4.6 measured
MedCode (Vals AI)49.1%42.4%Claude Opus 4.6
SimpleQA Verified47.0%41.0%Claude Opus 4.6
LMArena Text: science15191433Claude Opus 4.6
LMArena Text: medicine and healthcare15041399Claude Opus 4.6
LMArena Text: legal and government15121446Claude Opus 4.6
LMArena Text: business and finance14971439Claude Opus 4.6
FACTS Benchmark Suite41.5%35.0%Claude Opus 4.6
Neither model has a result on the other 4 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index80
Web design benchmarks for Claude Opus 4.6 and GPT-5.6 Luna
BenchmarkClaude Opus 4.6GPT-5.6 LunaLeader
Design Arena: websites12911255Claude Opus 4.6
Design Arena: UI components12811248Claude Opus 4.6
Design Arena: game dev12771194Claude Opus 4.6
Design Arena: data viz12791211Claude Opus 4.6
Design Arena: 3D12731121Claude Opus 4.6
Design Arena: all code categories12881231Claude Opus 4.6
Design Arena: SVG12271194Claude Opus 4.6
Design Arena: ASCII art12551142Claude Opus 4.6
LiveBench designNot measured76.0%Only GPT-5.6 Luna measured
GeneralLike-for-likePublic boards, shown as published, kept out of the index282
General benchmarks for Claude Opus 4.6 and GPT-5.6 Luna
BenchmarkClaude Opus 4.6GPT-5.6 LunaLeader
LiveBench data analysisNot measured78.0%Only GPT-5.6 Luna measured
Public Benefits Bench (Vals AI)Not measured61.2%Only GPT-5.6 Luna measured
SAGE (Vals AI)51.6%44.2%Claude Opus 4.6
MedScribe (Vals AI)86.7%84.4%Claude Opus 4.6
Vals Multimodal IndexNot measured69.1%Only GPT-5.6 Luna measured
IFBench53.1%Not measuredOnly Claude Opus 4.6 measured
Long context reasoning (AA-LCR)78.0%83.7%GPT-5.6 Luna
DTBench91.2%89.1%Claude Opus 4.6
LMCA55.8%48.5%Claude Opus 4.6
CL-bench20.7%Not measuredOnly Claude Opus 4.6 measured
Surface Evolver BenchNot measured61.9%Only GPT-5.6 Luna measured
Furniture assembly28.3%42.5%GPT-5.6 Luna
CL-bench Life17.0%Not measuredOnly Claude Opus 4.6 measured
LMArena Text15011431Claude Opus 4.6
LMArena Text: instruction following15211437Claude Opus 4.6
LMArena Text: creative writing15051396Claude Opus 4.6
LMArena Vision13161257Claude Opus 4.6
LMArena Text: English15111441Claude Opus 4.6
LMArena Text: non-English14881417Claude Opus 4.6
LMArena Text: Chinese15511470Claude Opus 4.6
LMArena Text: German15001455Claude Opus 4.6
LMArena Text: Japanese14881415Claude Opus 4.6
LMArena Text: Korean14641415Claude Opus 4.6
LMArena Text: French15121458Claude Opus 4.6
LMArena Text: Spanish15101446Claude Opus 4.6
LMArena Text: Russian14971427Claude Opus 4.6
LMArena Text: Polish14991405Claude Opus 4.6
LMArena Text: multi-turn15111434Claude Opus 4.6
LMArena Text: longer queries15181436Claude Opus 4.6
LMArena Text: writing and language15021419Claude Opus 4.6
LMArena Text: entertainment and media14921402Claude Opus 4.6
LMArena Vision: English13241263Claude Opus 4.6
LMArena Vision: Chinese13701294Claude Opus 4.6
LMArena Vision: reading text13261264Claude Opus 4.6
LMArena Vision: humor13141190Claude Opus 4.6
LMArena Vision: recognizing things1274Not measuredOnly Claude Opus 4.6 measured
LMArena Vision: creative writing13311257Claude Opus 4.6
LMArena Document15071457Claude Opus 4.6
Neither model has a result on the other 8 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for Claude Opus 4.6 and GPT-5.6 Luna
BenchmarkClaude Opus 4.6GPT-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

Claude Opus 4.6$0.018Fits 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

Claude Opus 4.6$0.325Fits 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

Claude Opus 4.6$1.25Fits 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 Claude Opus 4.6 and GPT-5.6 Luna
SpecificationAnthropic Claude Opus 4.6OpenAI GPT-5.6 Luna
MakerAnthropicOpenAI
WeightsNo public weights listedNo public weights listed
ReleasedFebruary 4, 2026July 9, 2026
Context window1M1.05M
Input $/Mtok$5.00$0.20
Output $/Mtok$25.00$1.20
Coding index57.258.0
Independent measurements behind it46
Cost per solved task$1.56$0.04
SourceOpenRouter listingOpenRouter listing

Questions

Is Claude Opus 4.6 better than GPT-5.6 Luna for coding?

Claude Opus 4.6 and GPT-5.6 Luna are level for coding, 57.2 against 58.0 on the Vibe Coding Index, so price and context decide. Pick Claude Opus 4.6 for work measured by LMArena WebDev or WeirdML, where it leads. Pick GPT-5.6 Luna for output tokens 20.8x cheaper ($1.20 vs $25.00 per million) and a lower cost per solved task ($0.04 against $1.56).

Which is cheaper, Claude Opus 4.6 or GPT-5.6 Luna?

Claude Opus 4.6 costs $5.00 per million input tokens and $25.00 per million output tokens; GPT-5.6 Luna costs $0.20 and $1.20. Per solved SWE-bench Verified task, Claude Opus 4.6 costs $1.56 and GPT-5.6 Luna $0.04.

Which has the bigger context window, Claude Opus 4.6 or GPT-5.6 Luna?

GPT-5.6 Luna, with 1.05M tokens against 1M.

How many benchmarks is the Claude Opus 4.6 vs GPT-5.6 Luna comparison based on?

86 benchmarks have a result for both models as of October 22, 2026. Claude Opus 4.6's coding index rests on 4 independent benchmarks and GPT-5.6 Luna's on 6. Where only one model has a result, the page says so instead of naming a winner.

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