Model comparison

GPT-4o vs GPT-5.6 Luna

GPT-5.6 Luna is the stronger model overall, scoring 54.7 to 28.5 on the Noometry Index.

Last verified . 32 shared benchmarks.

GPT-4o OpenAI

28.5

Rank #316 Confirmed

GPT-5.6 Luna OpenAI

54.7

Rank #24 Confirmed

Summary

  • They share 32 benchmarks with published results for both. GPT-4o scores higher in 0 categories and GPT-5.6 Luna in 10 categories; 10 gaps are clear of the uncertainty.
  • The widest gap is in math, where GPT-5.6 Luna leads 77.5 to 10.2.
  • The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 6.4% for GPT-4o and 98.3% for GPT-5.6 Luna.
  • GPT-5.6 Luna is cheaper at $0.20 / $1.20 per million input/output tokens, against $2.50 / $10 for GPT-4o.
  • GPT-5.6 Luna accepts more context: 1.05M tokens versus 128K.

Side by side

GPT-4o and GPT-5.6 Luna specifications
GPT-4oGPT-5.6 Luna
ProviderOpenAIOpenAI
Noometry Index28.554.7
Released2024-05-132026-07-09
WeightsProprietaryProprietary
Context window128K1.05M
Max output16K128K
Input $ / M tokens$2.50$0.20
Output $ / M tokens$10$1.20
Results tracked7251

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Category by category

Coding GPT-5.6 Luna leads

GPT-4o: 25.1 (#323), GPT-5.6 Luna: 53.9 (#25)

Coding benchmarks
BenchmarkGPT-4oGPT-5.6 Luna
WeirdML25.1%60.9%
LMArena Coding12971466
SWE-bench Verified31%—
DeepSWE—67.2%
FrontierCode—39.8%
SWE-bench Verified (bash only)21.6%—
Aider Polyglot45.3%—
CursorBench—35.9%
LMArena WebDev—1517
SciCode—53.6%
GSO0%—
BigCodeBench Instruct51.1%—
LiveBench Coding51.4%—
BigCodeBench Complete61.1%—
CadEval26%—
ALE-Bench—1,667
HumanEval+87.2%—
MBPP+72.2%—

Agentic & Tool Use GPT-5.6 Luna leads

GPT-4o: 20.8 (#133), GPT-5.6 Luna: 35.3 (#37)

Agentic & Tool Use benchmarks
BenchmarkGPT-4oGPT-5.6 Luna
BALROG32.3%45.6%
GDPval9.9%—
TheAgentCompany8.6%—
Cybench12.5%—
GDP.pdf—22.7%
LMArena Search1006—
METR Time Horizons40.8%—
Vending-Bench 2—4,095

Reasoning GPT-5.6 Luna leads

GPT-4o: 9.4 (#338), GPT-5.6 Luna: 47.5 (#38)

Reasoning benchmarks
BenchmarkGPT-4oGPT-5.6 Luna
ARC-AGI-20%59.5%
SimpleBench17.8%46.8%
ARC-AGI-14.5%88%
CritPt0%20.6%
Chess Puzzles13%40%
LMArena Hard Prompts12811452
DTBench64.5%89.1%
LMCA16.6%48.5%
Epoch Capabilities Index128.97156.32
Kagi LLM Benchmark—49.1%
NYT Connections (extended)—69.4%
EnigmaEval0.8%—
LiveBench Reasoning55.8%—
Mystery Game Puzzles—21%
LiveBench Data Analysis60.9%—
Surface Evolver Bench—61.9%
ForecastBench57.7—
LiveBench55.3%—

Math GPT-5.6 Luna leads

GPT-4o: 10.2 (#303), GPT-5.6 Luna: 77.5 (#12)

Math benchmarks
BenchmarkGPT-4oGPT-5.6 Luna
FrontierMath (Tiers 1-3)0.4%82.1%
OTIS Mock AIME 2024-20256.4%98.3%
LMArena Math12851455
FrontierMath Tier 4—61%
ProofBench—60%
Omni-MATH29.3%—
LiveBench Math49.5%—
MATH Level 553.3%—
FrontierMath (Feb 2025 set)0.3%—

Knowledge GPT-5.6 Luna leads

GPT-4o: 28.8 (#235), GPT-5.6 Luna: 58.6 (#31)

Knowledge benchmarks
BenchmarkGPT-4oGPT-5.6 Luna
GPQA Diamond49.2%91.6%
SimpleQA Verified26%41%
LMArena Expert12501479
Humanity's Last Exam2.7%—
MMLU-Pro71.3%—
Confabulations15.3%—
Vectara Hallucination Rate9.6%—
GPQA (HELM)52%—
MMLU88.1%—

Multimodal GPT-5.6 Luna leads

GPT-4o: 33.9 (#85), GPT-5.6 Luna: 43.0 (#22)

Multimodal benchmarks
BenchmarkGPT-4oGPT-5.6 Luna
LMArena Vision11371259
Video-MME71.9%—
GeoBench71%—
VPCT40%—
Blueprint-Bench 2—22.6%
Furniture Assembly—42.5%
LMArena Document—1457
ScienceQA88.5%—

Multilingual GPT-5.6 Luna leads

GPT-4o: 43.4 (#181), GPT-5.6 Luna: 53.0 (#73)

Multilingual benchmarks
BenchmarkGPT-4oGPT-5.6 Luna
LMArena Non-English12831418
LMArena Chinese12771469
LMArena French13031457
LMArena German12821459
LMArena Japanese12571416
LMArena Korean12341414
LMArena Russian12861428
LMArena Spanish12921445

Instruction Following GPT-5.6 Luna leads

GPT-4o: 66.8 (#202), GPT-5.6 Luna: 76.0 (#48)

Instruction Following benchmarks
BenchmarkGPT-4oGPT-5.6 Luna
LMArena Instruction Following12781440
LiveBench Instruction Following68.6%—
IFEval81.7%—

Long Context GPT-5.6 Luna leads

GPT-4o: 39.4 (#174), GPT-5.6 Luna: 43.9 (#78)

Long Context benchmarks
BenchmarkGPT-4oGPT-5.6 Luna
LMArena Longer Query12891437
Fiction.LiveBench66.7%—

Writing & Preference GPT-5.6 Luna leads

GPT-4o: 52.8 (#160), GPT-5.6 Luna: 68.3 (#27)

Writing & Preference benchmarks
BenchmarkGPT-4oGPT-5.6 Luna
LMArena Text13001432
LMArena Creative Writing12911397
LMArena Multi-Turn13021433
Short-Story Creative Writing81.8%—
EQ-Bench Creative Writing—1829
WildBench82.8%—
EQ-Bench 4—1156
LiveBench Language47.6%—

Frequently asked questions

Is GPT-4o better than GPT-5.6 Luna?

GPT-5.6 Luna is the stronger model overall, scoring 54.7 to 28.5 on the Noometry Index.

Which is cheaper, GPT-4o 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; GPT-4o lists at $2.50 and $10.

Is GPT-4o or GPT-5.6 Luna better for coding?

GPT-5.6 Luna scores higher on coding benchmarks: 53.9 versus 25.1 in the Noometry coding category.

Which has the bigger context window?

GPT-5.6 Luna does, with 1.05M tokens against 128K.

How many benchmarks do GPT-4o and GPT-5.6 Luna share?

32 benchmarks have published results for both models. GPT-4o has 72 scored results on Noometry and GPT-5.6 Luna has 51.

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