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Claude Opus 4.1 vs GPT-5.6 Luna

Updated October 21, 2026. 58 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.

Replace Claude Opus 4.1 Replace GPT-5.6 Luna
Claude Opus 4.1Anthropic
Coding
27.2
Overall
22.8
Output $/M
$75.00
12
GPT-5.6 LunaOpenAI
Coding
61.5
Overall
37.3
Output $/M
$1.20
45
vs boards won of 58 shared, 1 tied

Decision reading

Pick GPT-5.6 Luna for coding: it scores 61.5 on the Vibe Coding Index against 27.2 for Claude Opus 4.1.

Pick Claude Opus 4.1 when what matters is LMArena Text: coding or SimpleBench, where it leads.

Model AClaude Opus 4.1Anthropic27.2/1001 independent benchmarkNo cost per solved taskModel BGPT-5.6 LunaOpenAI61.5/1002 independent benchmarks$0.04 per solved task
Shared results
58
Claude Opus 4.1 only
13
GPT-5.6 Luna only
58
Like-for-like categories
7 of 9

Shared results can support a head-to-head reading. Results only one model has describe coverage, not superiority.

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 4.1 27.2 from 1 benchmark, GPT-5.6 Luna 61.5 from 2 benchmarks.
Widest category
Math, 33.6 points apart on average over 5 shared benchmarks.
Widest single gap
FrontierMath, tiers 1 to 3: Claude Opus 4.1 12.6% against GPT-5.6 Luna 82.1%, 69.5 points apart on a 0 to 100 scale.
Output price
Claude Opus 4.1 $75.00 against GPT-5.6 Luna $1.20 per million output tokens, 62.5x apart.
Context window
Claude Opus 4.1 takes 200K 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 4.1BarsGPT-5.6 LunaTies
Coding14
Intelligence02
Reasoning161 tie
Math05
Knowledge36
Web design26
General516
All shared boards12451 tie
CodingLike-for-likeFour of these boards feed the Vibe Coding Index14
Coding benchmarks for Claude Opus 4.1 and GPT-5.6 Luna
BenchmarkClaude Opus 4.1GPT-5.6 LunaLeader
LiveBench codingNot measured73.6%Only GPT-5.6 Luna measured
LMArena WebDev13901518GPT-5.6 Luna
AA Coding IndexNot measured71.4Only GPT-5.6 Luna measured
LiveCodeBench (Vals AI)66.5%Not measuredOnly Claude Opus 4.1 measured
SWE-bench Verified (Vals AI)Not measured93.0%Only GPT-5.6 Luna measured
Terminal-Bench 4 (Vals AI)Not measured11.6%Only GPT-5.6 Luna measured
Vibe Code Bench (Vals AI)Not measured77.1%Only GPT-5.6 Luna measured
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-Bench38.0%Not measuredOnly Claude Opus 4.1 measured
FrontierCodeNot measured39.8%Only GPT-5.6 Luna measured
WeirdML45.9%60.9%GPT-5.6 Luna
Cybench42.0%Not measuredOnly Claude Opus 4.1 measured
ALE-BenchNot measured1667.4Only GPT-5.6 Luna measured
LMArena Text: coding14791466Claude Opus 4.1
LMArena Text: software and IT14561463GPT-5.6 Luna
LMArena WebDev: ReactNot measured1508Only GPT-5.6 Luna measured
LMArena WebDev: HTML13991520GPT-5.6 Luna
LMArena WebDev: from an imageNot measured1517Only GPT-5.6 Luna measured
Neither model has a result on the other 13 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02
Intelligence benchmarks for Claude Opus 4.1 and GPT-5.6 Luna
BenchmarkClaude Opus 4.1GPT-5.6 LunaLeader
AA Intelligence Index22.837.3GPT-5.6 Luna
Epoch Capabilities Index144.1156.5GPT-5.6 Luna
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index18 boards, none shared
Agentic work benchmarks for Claude Opus 4.1 and GPT-5.6 Luna
BenchmarkClaude Opus 4.1GPT-5.6 LunaLeader
AA Agentic IndexNot measured42.1Only GPT-5.6 Luna 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
APEX-AgentsNot measured43.0%Only GPT-5.6 Luna measured
METR time horizons66.8%Not measuredOnly Claude Opus 4.1 measured
GDPval43.6%Not measuredOnly Claude Opus 4.1 measured
BALROGNot measured45.6%Only GPT-5.6 Luna measured
DeepResearch Bench48.3%Not measuredOnly Claude Opus 4.1 measured
Vending-Bench 2Not measured$4,095Only GPT-5.6 Luna measured
Neither model has a result on the other 21 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index16
Reasoning benchmarks for Claude Opus 4.1 and GPT-5.6 Luna
BenchmarkClaude Opus 4.1GPT-5.6 LunaLeader
GPQA Diamond76.3%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)77.5%85.0%GPT-5.6 Luna
GPQA Diamond (Artificial Analysis run)Not measured91.1%Only GPT-5.6 Luna measured
Humanity's Last Exam (Artificial Analysis run)Not measured39.5%Only GPT-5.6 Luna measured
GPQA Diamond (Epoch AI run)77.3%91.6%GPT-5.6 Luna
ARC-AGINot measured88.0%Only GPT-5.6 Luna measured
ARC-AGI-2Not measured59.5%Only GPT-5.6 Luna measured
SimpleBench60.0%46.8%Claude Opus 4.1
Chess puzzlesNot measured43.0%Only GPT-5.6 Luna measured
Mystery game puzzles21.0%21.0%Tie
EBR-bench7.9%Not measuredOnly Claude Opus 4.1 measured
VPCT35.0%Not measuredOnly Claude Opus 4.1 measured
LMArena Text: hard prompts14421451GPT-5.6 Luna
LMArena Text: expert14381478GPT-5.6 Luna
LMArena Text: hard prompts in English14511460GPT-5.6 Luna
LMArena Vision: diagramsNot measured1273Only GPT-5.6 Luna measured
LMArena Vision: homeworkNot measured1282Only GPT-5.6 Luna measured
Neither model has a result on the other 2 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index05
Math benchmarks for Claude Opus 4.1 and GPT-5.6 Luna
BenchmarkClaude Opus 4.1GPT-5.6 LunaLeader
AIME78.2%Not measuredOnly Claude Opus 4.1 measured
MATH 500 (Vals AI)95.4%Not measuredOnly Claude Opus 4.1 measured
MGSM (Vals AI)94.4%Not measuredOnly Claude Opus 4.1 measured
OTIS Mock AIME68.9%98.3%GPT-5.6 Luna
FrontierMath, tiers 1 to 312.6%82.1%GPT-5.6 Luna
FrontierMath, tier 42.4%61.0%GPT-5.6 Luna
ProofBenchNot measured60.0%Only GPT-5.6 Luna measured
LMArena Text: math14311459GPT-5.6 Luna
LMArena Text: mathematical work14341470GPT-5.6 Luna
Neither model has a result on the other 4 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index36
Knowledge benchmarks for Claude Opus 4.1 and GPT-5.6 Luna
BenchmarkClaude Opus 4.1GPT-5.6 LunaLeader
MMLU Pro87.9%86.0%Claude Opus 4.1
LegalBench (Vals AI)83.5%84.0%GPT-5.6 Luna
CorpFin (Vals AI)Not measured64.2%Only GPT-5.6 Luna measured
TaxEval (Vals AI)73.7%76.2%GPT-5.6 Luna
MortgageTax (Vals AI)61.1%67.3%GPT-5.6 Luna
MedQA (Vals AI)93.6%Not measuredOnly Claude Opus 4.1 measured
MedCode (Vals AI)47.2%42.4%Claude Opus 4.1
SimpleQA VerifiedNot measured41.0%Only GPT-5.6 Luna measured
LMArena Text: science14221433GPT-5.6 Luna
LMArena Text: medicine and healthcare14161399Claude Opus 4.1
LMArena Text: legal and government14211446GPT-5.6 Luna
LMArena Text: business and finance14061439GPT-5.6 Luna
Neither model has a result on the other 5 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index26
Web design benchmarks for Claude Opus 4.1 and GPT-5.6 Luna
BenchmarkClaude Opus 4.1GPT-5.6 LunaLeader
Design Arena: websites11771256GPT-5.6 Luna
Design Arena: UI components11641250GPT-5.6 Luna
Design Arena: game dev11721196GPT-5.6 Luna
Design Arena: data viz11661212GPT-5.6 Luna
Design Arena: 3D11531121Claude Opus 4.1
Design Arena: all code categories11711231GPT-5.6 Luna
Design Arena: SVG11521193GPT-5.6 Luna
Design Arena: ASCII art11671144Claude Opus 4.1
LiveBench designNot measured76.0%Only GPT-5.6 Luna measured
GeneralLike-for-likePublic boards, shown as published, kept out of the index516
General benchmarks for Claude Opus 4.1 and GPT-5.6 Luna
BenchmarkClaude Opus 4.1GPT-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)31.4%44.2%GPT-5.6 Luna
MedScribe (Vals AI)73.9%84.4%GPT-5.6 Luna
Vals Multimodal IndexNot measured69.1%Only GPT-5.6 Luna measured
Long context reasoning (AA-LCR)Not measured83.7%Only GPT-5.6 Luna measured
DTBench80.0%89.1%GPT-5.6 Luna
LMCA37.1%48.5%GPT-5.6 Luna
Creative writing (Lech Mazur)84.7%Not measuredOnly Claude Opus 4.1 measured
Surface Evolver BenchNot measured61.9%Only GPT-5.6 Luna measured
Furniture assemblyNot measured42.5%Only GPT-5.6 Luna measured
LMArena Text14191431GPT-5.6 Luna
LMArena Text: instruction following14351437GPT-5.6 Luna
LMArena Text: creative writing14121396Claude Opus 4.1
LMArena VisionNot measured1257Only GPT-5.6 Luna measured
LMArena Text: English14331441GPT-5.6 Luna
LMArena Text: non-English14051417GPT-5.6 Luna
LMArena Text: Chinese14271470GPT-5.6 Luna
LMArena Text: German14131455GPT-5.6 Luna
LMArena Text: Japanese13771415GPT-5.6 Luna
LMArena Text: Korean13811415GPT-5.6 Luna
LMArena Text: French14331458GPT-5.6 Luna
LMArena Text: Spanish14481446Claude Opus 4.1
LMArena Text: Russian14221427GPT-5.6 Luna
LMArena Text: Polish14131405Claude Opus 4.1
LMArena Text: multi-turn14441434Claude Opus 4.1
LMArena Text: longer queries14551436Claude Opus 4.1
LMArena Text: writing and language14181419GPT-5.6 Luna
LMArena Text: entertainment and media13981402GPT-5.6 Luna
LMArena Vision: EnglishNot measured1263Only GPT-5.6 Luna measured
LMArena Vision: ChineseNot measured1294Only GPT-5.6 Luna measured
LMArena Vision: reading textNot measured1264Only GPT-5.6 Luna measured
LMArena Vision: humorNot measured1190Only GPT-5.6 Luna measured
LMArena Vision: creative writingNot measured1257Only GPT-5.6 Luna measured
LMArena DocumentNot measured1457Only 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 Claude Opus 4.1 and GPT-5.6 Luna
BenchmarkClaude Opus 4.1GPT-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 4.1$0.052Fits 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 4.1$0.975Fits 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 4.1$3.75Exceeds the context window
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 4.1 and GPT-5.6 Luna
SpecificationAnthropic Claude Opus 4.1OpenAI GPT-5.6 Luna
MakerAnthropicOpenAI
WeightsNo public weights listedNo public weights listed
ReleasedAugust 5, 2025July 9, 2026
Context window200K1.05M
Input $/Mtok$15.00$0.20
Output $/Mtok$75.00$1.20
Coding index27.261.5
Independent measurements behind it12
Cost per solved taskNot computable$0.04
SourceOpenRouter listingOpenRouter listing

Questions

Is Claude Opus 4.1 better than GPT-5.6 Luna for coding?

Pick GPT-5.6 Luna for coding: it scores 61.5 on the Vibe Coding Index against 27.2 for Claude Opus 4.1. Pick Claude Opus 4.1 when what matters is LMArena Text: coding or SimpleBench, where it leads.

Which is cheaper, Claude Opus 4.1 or GPT-5.6 Luna?

Claude Opus 4.1 costs $15.00 per million input tokens and $75.00 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, Claude Opus 4.1 or GPT-5.6 Luna?

GPT-5.6 Luna, with 1.05M tokens against 200K.

How many benchmarks is the Claude Opus 4.1 vs GPT-5.6 Luna comparison based on?

58 benchmarks have a result for both models as of October 21, 2026. Claude Opus 4.1's coding index rests on 1 independent benchmark and GPT-5.6 Luna's on 2. Where only one model has a result, the page says so instead of naming a winner.

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