Model comparison

Claude Opus 5 vs GPT-5.6 Luna

Claude Opus 5 is the stronger model overall, scoring 67.8 to 54.6 on the Noometry Index. GPT-5.6 Luna costs 22× less per token, which makes it the better buy when Claude Opus 5's lead doesn't matter for your workload.

Last verified . 50 shared benchmarks.

Claude Opus 5 Anthropic

67.8

Rank #4 Confirmed

GPT-5.6 Luna OpenAI

54.6

Rank #30 Confirmed

Summary

  • They share 50 benchmarks with published results for both. Claude Opus 5 scores higher in 10 categories and GPT-5.6 Luna in 0 categories; 10 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where Claude Opus 5 leads 77.2 to 47.6.
  • The biggest single-benchmark swing is ProofBench: 99% for Claude Opus 5 and 60% for GPT-5.6 Luna.
  • GPT-5.6 Luna is cheaper at $0.20 / $1.20 per million input/output tokens, against $5 / $25 for Claude Opus 5.
  • GPT-5.6 Luna accepts more context: 1.05M tokens versus 1M.

Side by side

Claude Opus 5 and GPT-5.6 Luna specifications
Claude Opus 5GPT-5.6 Luna
ProviderAnthropicOpenAI
Noometry Index67.854.6
Released2026-07-242026-07-09
WeightsProprietaryProprietary
Context window1M1.05M
Max output128K128K
Input $ / M tokens$5$0.20
Output $ / M tokens$25$1.20
Results tracked5752

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Category by category

Coding Claude Opus 5 leads

Claude Opus 5: 67.5 (#5), GPT-5.6 Luna: 54.5 (#28)

Coding benchmarks
BenchmarkClaude Opus 5GPT-5.6 Luna
DeepSWE73.6%67.2%
FrontierCode53.4%39.8%
CursorBench46.6%35.9%
LMArena WebDev16911519
SciCode56.4%53.6%
WeirdML91.8%60.9%
LMArena Coding15341466
ALE-Bench2,1651,667
FrontierSWE52%—

Agentic & Tool Use Claude Opus 5 leads

Claude Opus 5: 55.6 (#1), GPT-5.6 Luna: 34.4 (#45)

Agentic & Tool Use benchmarks
BenchmarkClaude Opus 5GPT-5.6 Luna
APEX-Agents65.8%43%
BALROG63.4%45.6%
GDP.pdf24%22.7%
Vending-Bench 211,1824,095
OSWorld 2.031.4%—
τ²-bench Banking48.7%—
PostTrainBench35%—
GBAEval79.6%—

Reasoning Claude Opus 5 leads

Claude Opus 5: 77.2 (#4), GPT-5.6 Luna: 47.6 (#43)

Reasoning benchmarks
BenchmarkClaude Opus 5GPT-5.6 Luna
ARC-AGI-290.4%59.5%
SimpleBench80.6%46.8%
NYT Connections (extended)94.3%69.4%
ARC-AGI-197.5%88%
CritPt29.1%20.6%
Chess Puzzles42%40%
LMArena Hard Prompts15261451
Mystery Game Puzzles59%21%
DTBench97.9%89.1%
LMCA64.5%48.5%
Epoch Capabilities Index162.78156.39
Kagi LLM Benchmark—49.1%
EBR-Bench45.7%—
Surface Evolver Bench—61.9%
Bench to the Future 30.12—

Math Claude Opus 5 leads

Claude Opus 5: 86.2 (#8), GPT-5.6 Luna: 77.7 (#14)

Math benchmarks
BenchmarkClaude Opus 5GPT-5.6 Luna
FrontierMath (Tiers 1-3)85.6%82.1%
FrontierMath Tier 473.2%61%
OTIS Mock AIME 2024-202598.9%98.3%
ProofBench99%60%
LMArena Math15311458

Knowledge Claude Opus 5 leads

Claude Opus 5: 66.8 (#9), GPT-5.6 Luna: 58.5 (#34)

Knowledge benchmarks
BenchmarkClaude Opus 5GPT-5.6 Luna
GPQA Diamond93.9%91.6%
SimpleQA Verified59.9%41%
LMArena Expert15571478

Multimodal Claude Opus 5 leads

Claude Opus 5: 50.8 (#8), GPT-5.6 Luna: 42.7 (#28)

Multimodal benchmarks
BenchmarkClaude Opus 5GPT-5.6 Luna
LMArena Vision13191258
Blueprint-Bench 230.4%22.6%
Furniture Assembly60.8%42.5%
LMArena Document15161457

Multilingual Claude Opus 5 leads

Claude Opus 5: 58.8 (#4), GPT-5.6 Luna: 52.8 (#78)

Multilingual benchmarks
BenchmarkClaude Opus 5GPT-5.6 Luna
LMArena Non-English15011417
LMArena Chinese15741470
LMArena French15191456
LMArena German15241454
LMArena Japanese15161411
LMArena Korean15211415
LMArena Russian15071428
LMArena Spanish15191448

Instruction Following Claude Opus 5 leads

Claude Opus 5: 79.2 (#7), GPT-5.6 Luna: 75.6 (#57)

Instruction Following benchmarks
BenchmarkClaude Opus 5GPT-5.6 Luna
LMArena Instruction Following15171437

Long Context Claude Opus 5 leads

Claude Opus 5: 46.5 (#21), GPT-5.6 Luna: 43.9 (#82)

Long Context benchmarks
BenchmarkClaude Opus 5GPT-5.6 Luna
LMArena Longer Query15151436

Writing & Preference Claude Opus 5 leads

Claude Opus 5: 79.2 (#1), GPT-5.6 Luna: 68.0 (#29)

Writing & Preference benchmarks
BenchmarkClaude Opus 5GPT-5.6 Luna
LMArena Text15071431
LMArena Creative Writing14911396
EQ-Bench Creative Writing21331829
EQ-Bench 413851156
LMArena Multi-Turn14991434

Frequently asked questions

Is Claude Opus 5 better than GPT-5.6 Luna?

Claude Opus 5 is the stronger model overall, scoring 67.8 to 54.6 on the Noometry Index. GPT-5.6 Luna costs 22× less per token, which makes it the better buy when Claude Opus 5's lead doesn't matter for your workload.

Which is cheaper, Claude Opus 5 or GPT-5.6 Luna?

GPT-5.6 Luna is cheaper. It lists at $0.20 per million input tokens and $1.20 per million output tokens; Claude Opus 5 lists at $5 and $25.

Is Claude Opus 5 or GPT-5.6 Luna better for coding?

Claude Opus 5 scores higher on coding benchmarks: 67.5 versus 54.5 in the Noometry coding category.

Which has the bigger context window?

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

How many benchmarks do Claude Opus 5 and GPT-5.6 Luna share?

50 benchmarks have published results for both models. Claude Opus 5 has 57 scored results on Noometry and GPT-5.6 Luna has 52.

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