GPT-5.6 Luna (Medium) vs GPT-6 Astra (Medium)
Which is better for the money: GPT-5.6 Luna (Medium) by OpenAI or GPT-6 Astra (Medium) by OpenAI? Intelligence, total benchmark cost, and end-to-end time from Artificial Analysis & other sources, snapshot 2026-10-26.
Trade-off
Verdict
Depends on your budget
GPT-6 Astra (Medium) scores 24.6 points higher (49.6 vs 25.0) but costs 55× as much to run the benchmark ($2434 vs $44.3; flagship vs budget cost classes). They are not alternatives at one budget: pick GPT-6 Astra (Medium) when you need intelligence above 25.0, and GPT-5.6 Luna (Medium) when 25.0 is enough.
| Metric | GPT-5.6 Luna (Medium) | GPT-6 Astra (Medium) | Difference |
|---|---|---|---|
| Intelligence (higher is better) | 25.0 | 49.6 | +98.4% GPT-6 Astra (Medium) is 98.4% more intelligent |
| Total AA cost (lower is better) | $44.32 | $2,434.12 | +5392.1% GPT-6 Astra (Medium) is 55× more expensive |
| End-to-end time (lower is better) | 6.64s | 14.89s | +124.2% GPT-6 Astra (Medium) is 124.2% slower |
| Price per 1M tokens (in / out) | $0.20 / $1.20 | $10.0 / $50.0 | |
| Input modalities | Text, Image | Text, Image |
GPT-6 Astra (Medium) vs GPT-5.6 Luna (Medium): 98.4% more intelligence, 5392.1% more cost to run the AA benchmark, and 124.2% slower end-to-end.
Today's Pareto frontier
Against the frontier
- GPT-5.6 Luna (Medium) is off the frontier: at the same or lower cost, GPT-6 Luna (Medium) scores 29.90 for $31.2.
- GPT-6 Astra (Medium) is off the frontier: at the same or lower cost, Claude Opus 5.5 (High, Default Fallback) scores 53.60 for $2172.
GPT-5.6 Luna (Medium)GPT-6 Astra (Medium)Today's Pareto frontierEvery other model
Matchup
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Accept: text/markdown or ?format=md returns this page as Markdown. JSON: /api/v1/compare/gpt-5-6-luna-medium/gpt-6-astra-medium · Markdown: /api/v1/compare/gpt-5-6-luna-medium/gpt-6-astra-medium?format=md · llms.txt · agent skill