OpenAIGPT-5.4 miniVSOpenAIGPT-5.6 Luna

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

Our Take

If your budget allows, GPT-5.6 Luna is the superior choice here, offering a clear benchmark advantage while carrying only a slight price premium (1.3x). We recommend choosing GPT-5.4 mini only if you need to optimize costs for very high-volume pipelines.

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Model Specs

GPT-5.4 mini

Website

Benchmarks & Scores

Coding (swe-bench-pro)

54.4%

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

Reasoning (gpqa-diamond)

87.5%

graduate-level science QA

Cost & Context

Cost (per 1M tokens)1.3x cheaper

$1.69Input: $0.75 | Output: $4.50

Context Window

400k tokens

Model Specs

GPT-5.6 Luna

Website

Benchmarks & Scores

Coding (swe-bench-pro)Winner (+8.3%)

62.7%

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

Reasoning (gpqa-diamond)Winner (+4.8%)

92.3%

graduate-level science QA

Cost & Context

Cost (per 1M tokens)

$2.25Input: $1.00 | Output: $6.00

Context WindowLarger

1.05M tokens

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

GPT-5.4 mini is cheaper than GPT-5.6 Luna. GPT-5.4 mini has a blended cost of $1.69/1M tokens, which is about 1.3x 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 mini which scores 54.4%.

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