OpenAIGPT-5.4 nanoVSOpenAIGPT-5.6 Luna

Analysis by:the whichllmmodel Editorial Team|Updated: June 2026

Our Take

This matchup represents a clear tradeoff between peak intelligence and budget efficiency. GPT-5.6 Luna is noticeably superior (holding a 9.9% average lead in benchmarks), but it carries a significant 4.9x price premium. Choose GPT-5.6 Luna if you need top-tier reasoning or code debugging, but for high-volume pipelines, GPT-5.4 nano is the smarter business decision.

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Model Specs

GPT-5.4 nano

Website

Benchmarks & Scores

Coding (swe-bench-pro)

52.4%

excellent at multi-file repositories, autonomous agents, and industrial codebases

Reasoning (gpqa-diamond)

82.8%

graduate-level science QA

Cost & Context

Cost (per 1M tokens)4.9x cheaper

$0.46Input: $0.20 | Output: $1.25

Context Window

400k tokens

Model Specs

GPT-5.6 Luna

Website

Benchmarks & Scores

Coding (swe-bench-pro)Winner (+10.3%)

62.7%

excellent at multi-file repositories, autonomous agents, and industrial codebases

Reasoning (gpqa-diamond)Winner (+9.5%)

92.3%

graduate-level science QA

Cost & Context

Cost (per 1M tokens)

$2.25Input: $1.00 | Output: $6.00

Context WindowLarger

1.05M tokens

Read our data collection methodology

Frequently Asked Questions about GPT-5.4 nano vs GPT-5.6 Luna

GPT-5.4 nano is cheaper than GPT-5.6 Luna. GPT-5.4 nano has a blended cost of $0.46/1M tokens, which is about 4.9x cheaper than GPT-5.6 Luna at $2.25/1M tokens.

GPT-5.6 Luna is better for coding tasks on this benchmark. It scores 62.7% on swe-bench-pro (excellent at multi-file repositories, autonomous agents, and industrial codebases) compared to GPT-5.4 nano which scores 52.4%.

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