GPT-5.5 (Medium) vs GPT-6 Luna (Low)
Which is better for the money: GPT-5.5 (Medium) by OpenAI or GPT-6 Luna (Low) by OpenAI? Intelligence, total benchmark cost, and end-to-end time from Artificial Analysis & other sources, snapshot 2026-10-24.
Trade-off
Verdict
Depends on your budget
GPT-5.5 (Medium) scores 12.3 points higher (33.8 vs 21.5) but costs 197× as much to run the benchmark ($2095 vs $10.6; flagship vs budget cost classes). They are not alternatives at one budget: pick GPT-5.5 (Medium) when you need intelligence above 21.5, and GPT-6 Luna (Low) when 21.5 is enough.
| Metric | GPT-5.5 (Medium) | GPT-6 Luna (Low) | Difference |
|---|---|---|---|
| Intelligence (higher is better) | 33.8 | 21.5 | −36.4% GPT-6 Luna (Low) is 36.4% less intelligent |
| Total AA cost (lower is better) | $2,095.12 | $10.63 | −99.5% GPT-6 Luna (Low) is 99.5% cheaper |
| End-to-end time (lower is better) | 9.73s | 6.60s | −32.2% GPT-6 Luna (Low) is 32.2% faster |
| Price per 1M tokens (in / out) | $5.00 / $30.0 | $0.10 / $0.50 | |
| Input modalities | Text, Image | Text, Image |
GPT-6 Luna (Low) vs GPT-5.5 (Medium): 36.4% less intelligence, 99.5% less cost to run the AA benchmark, and 32.2% faster end-to-end.
Today's Pareto frontier
Against the frontier
- GPT-5.5 (Medium) is off the frontier: at the same or lower cost, GPT-6.1 Sol (Max) scores 51.80 for $1082.
- GPT-6 Luna (Low) is on today's frontier: nothing is both smarter and cheaper.
GPT-5.5 (Medium)GPT-6 Luna (Low)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-5-5-medium/gpt-6-luna-low · Markdown: /api/v1/compare/gpt-5-5-medium/gpt-6-luna-low?format=md · llms.txt · agent skill