Model comparison

GPT-5 vs GPT-6 Luna

GPT-6 Luna is the stronger model overall, scoring 53.3 to 50.9 on the Noometry Index.

Last verified . 35 shared benchmarks.

GPT-5 OpenAI

50.9

Rank #45 Confirmed

GPT-6 Luna OpenAI

53.3

Rank #36 Confirmed

Summary

  • They share 35 benchmarks with published results for both. GPT-5 scores higher in 4 categories and GPT-6 Luna in 6 categories; 6 gaps are clear of the uncertainty.
  • The widest gap is in long context, where GPT-5 leads 69.5 to 43.0.
  • The biggest single-benchmark swing is ARC-AGI-2: 9.9% for GPT-5 and 59.3% for GPT-6 Luna.
  • GPT-6 Luna is cheaper at $0.10 / $0.50 per million input/output tokens, against $1.25 / $10 for GPT-5.
  • GPT-6 Luna accepts more context: 1.05M tokens versus 400K.

Side by side

GPT-5 and GPT-6 Luna specifications
GPT-5GPT-6 Luna
ProviderOpenAIOpenAI
Noometry Index50.953.3
Released2025-08-072026-09-22
WeightsProprietaryProprietary
Context window400K1.05M
Max output128K128K
Input $ / M tokens$1.25$0.10
Output $ / M tokens$10$0.50
Results tracked6942

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Category by category

Coding GPT-6 Luna leads

GPT-5: 50.3 (#47), GPT-6 Luna: 55.5 (#25)

Coding benchmarks
BenchmarkGPT-5GPT-6 Luna
LMArena WebDev14181581
SciCode42.9%54.6%
LMArena Coding14361439
ALE-Bench1,1621,577
SWE-bench Verified73.6%—
DeepSWE—66.6%
FrontierCode—42.4%
SWE-bench Verified (bash only)65%—
Aider Polyglot88%—
GSO6.9%—
WeirdML60.7%—
AlgoTune1.67—

Agentic & Tool Use Too close to call

GPT-5: 33.1 (#56), GPT-6 Luna: 33.3 (#54)

Agentic & Tool Use benchmarks
BenchmarkGPT-5GPT-6 Luna
Terminal-Bench49.6%—
APEX-Agents—44.3%
GDPval34.8%—
Remote Labor Index1.7%—
DeepResearch Bench49.6%—
BALROG32.8%—
GDP.pdf—23%
LMArena Search1133—
METR Time Horizons69.6%—

Reasoning GPT-6 Luna leads

GPT-5: 38.3 (#64), GPT-6 Luna: 48.2 (#41)

Reasoning benchmarks
BenchmarkGPT-5GPT-6 Luna
ARC-AGI-29.9%59.3%
ARC-AGI-165.7%86.7%
CritPt12.6%19.4%
Chess Puzzles37%31%
LMArena Hard Prompts14161411
Mystery Game Puzzles23%7%
DTBench90.7%90.1%
LMCA40%44.5%
Epoch Capabilities Index150156.28
SimpleBench56.7%—
Kagi LLM Benchmark72.7%—
NYT Connections (extended)—68.7%
EnigmaEval10.5%—
EBR-Bench12.7%—
ForecastBench61.4—

Math GPT-6 Luna leads

GPT-5: 55.0 (#44), GPT-6 Luna: 76.1 (#15)

Math benchmarks
BenchmarkGPT-5GPT-6 Luna
FrontierMath (Tiers 1-3)55.4%78.9%
FrontierMath Tier 422%56.1%
OTIS Mock AIME 2024-202591.4%98.9%
ProofBench18%64%
LMArena Math14071416
Omni-MATH64.7%—
MATH Level 598.1%—
FrontierMath (Feb 2025 set)32.4%—
FrontierMath Tier 4 (v1)12.5%—

Knowledge Too close to call

GPT-5: 56.6 (#43), GPT-6 Luna: 57.0 (#41)

Knowledge benchmarks
BenchmarkGPT-5GPT-6 Luna
GPQA Diamond86.2%90.5%
SimpleQA Verified50.1%41.4%
LMArena Expert14191444
Humanity's Last Exam25.3%—
MMLU-Pro86.3%—
Confabulations10.3%—
Vectara Hallucination Rate14.7%—
GPQA (HELM)79.2%—

Multimodal GPT-5 leads

GPT-5: 46.8 (#13), GPT-6 Luna: 42.4 (#30)

Multimodal benchmarks
BenchmarkGPT-5GPT-6 Luna
LMArena Vision12321217
GeoBench81%—
VPCT66%—
Blueprint-Bench 2—31.2%
Furniture Assembly—44.2%

Multilingual Too close to call

GPT-5: 51.4 (#110), GPT-6 Luna: 50.5 (#117)

Multilingual benchmarks
BenchmarkGPT-5GPT-6 Luna
LMArena Non-English13971386
LMArena Chinese14221433
LMArena French14101420
LMArena German14161369
LMArena Japanese14091369
LMArena Korean13601360
LMArena Russian14061394
LMArena Spanish13991393

Instruction Following Too close to call

GPT-5: 73.8 (#113), GPT-6 Luna: 74.3 (#99)

Instruction Following benchmarks
BenchmarkGPT-5GPT-6 Luna
LMArena Instruction Following13881409
IFEval87.5%—

Long Context GPT-5 leads

GPT-5: 69.5 (#2), GPT-6 Luna: 43.0 (#111)

Long Context benchmarks
BenchmarkGPT-5GPT-6 Luna
LMArena Longer Query13991409
Fiction.LiveBench97.2%—

Writing & Preference GPT-5 leads

GPT-5: 63.4 (#65), GPT-6 Luna: 58.3 (#119)

Writing & Preference benchmarks
BenchmarkGPT-5GPT-6 Luna
LMArena Text14061391
LMArena Creative Writing13651363
LMArena Multi-Turn14261396
Short-Story Creative Writing86%—
EQ-Bench Creative Writing1627—
WildBench85.7%—

Frequently asked questions

Is GPT-5 better than GPT-6 Luna?

GPT-6 Luna is the stronger model overall, scoring 53.3 to 50.9 on the Noometry Index.

Which is cheaper, GPT-5 or GPT-6 Luna?

GPT-6 Luna is cheaper. It lists at $0.10 per million input tokens and $0.50 per million output tokens; GPT-5 lists at $1.25 and $10.

Is GPT-5 or GPT-6 Luna better for coding?

GPT-6 Luna scores higher on coding benchmarks: 55.5 versus 50.3 in the Noometry coding category.

Which has the bigger context window?

GPT-6 Luna does, with 1.05M tokens against 400K.

How many benchmarks do GPT-5 and GPT-6 Luna share?

35 benchmarks have published results for both models. GPT-5 has 69 scored results on Noometry and GPT-6 Luna has 42.

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