Model comparison

GPT-5.4 vs GPT-6 Luna

GPT-5.4 is the stronger model overall, scoring 59.4 to 53.3 on the Noometry Index. GPT-6 Luna costs 28× less per token, which makes it the better buy when GPT-5.4's lead doesn't matter for your workload.

Last verified . 40 shared benchmarks.

GPT-5.4 OpenAI

59.4

Rank #16 Confirmed

GPT-6 Luna OpenAI

53.3

Rank #36 Confirmed

Summary

  • They share 40 benchmarks with published results for both. GPT-5.4 scores higher in 8 categories and GPT-6 Luna in 2 categories; 10 gaps are clear of the uncertainty.
  • The widest gap is in writing & preference, where GPT-5.4 leads 71.9 to 58.3.
  • The biggest single-benchmark swing is Mystery Game Puzzles: 37% for GPT-5.4 and 7% for GPT-6 Luna.
  • GPT-6 Luna is cheaper at $0.10 / $0.50 per million input/output tokens, against $2.50 / $15 for GPT-5.4.

Side by side

GPT-5.4 and GPT-6 Luna specifications
GPT-5.4GPT-6 Luna
ProviderOpenAIOpenAI
Noometry Index59.453.3
Released2026-03-052026-09-22
WeightsProprietaryProprietary
Context window1.05M1.05M
Max output128K128K
Input $ / M tokens$2.50$0.10
Output $ / M tokens$15$0.50
Results tracked6842

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Category by category

Coding GPT-6 Luna leads

GPT-5.4: 52.6 (#33), GPT-6 Luna: 55.5 (#25)

Coding benchmarks
BenchmarkGPT-5.4GPT-6 Luna
DeepSWE51.8%66.6%
LMArena WebDev14651581
SciCode56.6%54.6%
LMArena Coding14971439
ALE-Bench1,6071,577
SWE-bench Verified76.9%—
FrontierCode—42.4%
GSO31.4%—
WeirdML77.7%—
MirrorCode15.6%—
AlgoTune1.85—

Agentic & Tool Use GPT-5.4 leads

GPT-5.4: 46.5 (#13), GPT-6 Luna: 33.3 (#54)

Agentic & Tool Use benchmarks
BenchmarkGPT-5.4GPT-6 Luna
APEX-Agents52.4%44.3%
Terminal-Bench81.8%—
τ²-bench Banking39.4%—
DeepResearch Bench35.1%—
PostTrainBench19%—
GBAEval45.1%—
GDP.pdf—23%
LMArena Search1197—
METR Time Horizons74.3%—
Vending-Bench 26,144—

Reasoning GPT-5.4 leads

GPT-5.4: 61.8 (#19), GPT-6 Luna: 48.2 (#41)

Reasoning benchmarks
BenchmarkGPT-5.4GPT-6 Luna
ARC-AGI-274%59.3%
NYT Connections (extended)91.3%68.7%
ARC-AGI-193.7%86.7%
CritPt23.4%19.4%
Chess Puzzles44%31%
LMArena Hard Prompts14851411
Mystery Game Puzzles37%7%
DTBench94.4%90.1%
LMCA52%44.5%
Epoch Capabilities Index156.81156.28
Kagi LLM Benchmark63.8%—
EnigmaEval16%—
Thematic Generalization80%—
EBR-Bench25.4%—
ForecastBench59.5—

Math GPT-6 Luna leads

GPT-5.4: 73.5 (#19), GPT-6 Luna: 76.1 (#15)

Knowledge GPT-5.4 leads

GPT-5.4: 65.3 (#14), GPT-6 Luna: 57.0 (#41)

Knowledge benchmarks
BenchmarkGPT-5.4GPT-6 Luna
GPQA Diamond93.3%90.5%
SimpleQA Verified45.1%41.4%
LMArena Expert15071444
Humanity's Last Exam36.2%—
Vectara Hallucination Rate7%—

Multimodal GPT-5.4 leads

GPT-5.4: 43.7 (#20), GPT-6 Luna: 42.4 (#30)

Multimodal benchmarks
BenchmarkGPT-5.4GPT-6 Luna
LMArena Vision13031217
Blueprint-Bench 227.1%31.2%
Furniture Assembly37.5%44.2%
LMArena Document1471—

Multilingual GPT-5.4 leads

GPT-5.4: 56.2 (#23), GPT-6 Luna: 50.5 (#117)

Multilingual benchmarks
BenchmarkGPT-5.4GPT-6 Luna
LMArena Non-English14651386
LMArena Chinese15191433
LMArena French14931420
LMArena German14721369
LMArena Japanese14851369
LMArena Korean14481360
LMArena Russian14801394
LMArena Spanish14541393

Instruction Following GPT-5.4 leads

GPT-5.4: 77.1 (#27), GPT-6 Luna: 74.3 (#99)

Instruction Following benchmarks
BenchmarkGPT-5.4GPT-6 Luna
LMArena Instruction Following14691409

Long Context GPT-5.4 leads

GPT-5.4: 50.3 (#8), GPT-6 Luna: 43.0 (#111)

Long Context benchmarks
BenchmarkGPT-5.4GPT-6 Luna
LMArena Longer Query14731409
CL-bench27.9%—
CL-bench Life21.7%—

Writing & Preference GPT-5.4 leads

GPT-5.4: 71.9 (#17), GPT-6 Luna: 58.3 (#119)

Writing & Preference benchmarks
BenchmarkGPT-5.4GPT-6 Luna
LMArena Text14691391
LMArena Creative Writing14391363
LMArena Multi-Turn14821396
EQ-Bench Creative Writing1840—
EQ-Bench 41272—

Frequently asked questions

Is GPT-5.4 better than GPT-6 Luna?

GPT-5.4 is the stronger model overall, scoring 59.4 to 53.3 on the Noometry Index. GPT-6 Luna costs 28× less per token, which makes it the better buy when GPT-5.4's lead doesn't matter for your workload.

Which is cheaper, GPT-5.4 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-5.4 lists at $2.50 and $15.

Is GPT-5.4 or GPT-6 Luna better for coding?

GPT-6 Luna scores higher on coding benchmarks: 55.5 versus 52.6 in the Noometry coding category.

Which has the bigger context window?

Both accept 1.05M tokens.

How many benchmarks do GPT-5.4 and GPT-6 Luna share?

40 benchmarks have published results for both models. GPT-5.4 has 68 scored results on Noometry and GPT-6 Luna has 42.

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