GPT-5.5 (High) vs GPT-6 Luna (Medium)
Which is better for the money: GPT-5.5 (High) by OpenAI or GPT-6 Luna (Medium) 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 (High) scores 7.1 points higher (37.0 vs 29.9) but costs 109× as much to run the benchmark ($3411 vs $31.2; flagship vs budget cost classes). They are not alternatives at one budget: pick GPT-5.5 (High) when you need intelligence above 29.9, and GPT-6 Luna (Medium) when 29.9 is enough.
| Metric | GPT-5.5 (High) | GPT-6 Luna (Medium) | Difference |
|---|---|---|---|
| Intelligence (higher is better) | 37.0 | 29.9 | −19.2% GPT-6 Luna (Medium) is 19.2% less intelligent |
| Total AA cost (lower is better) | $3,410.76 | $31.17 | −99.1% GPT-6 Luna (Medium) is 99.1% cheaper |
| End-to-end time (lower is better) | 19.79s | 8.25s | −58.3% GPT-6 Luna (Medium) is 58.3% faster |
| Price per 1M tokens (in / out) | $5.00 / $30.0 | $0.10 / $0.50 | |
| Input modalities | Text, Image | Text, Image |
GPT-6 Luna (Medium) vs GPT-5.5 (High): 19.2% less intelligence, 99.1% less cost to run the AA benchmark, and 58.3% faster end-to-end.
Today's Pareto frontier
Against the frontier
- GPT-5.5 (High) is off the frontier: at the same or lower cost, Kimi K3.1 Pro scores 55.10 for $3117.
- GPT-6 Luna (Medium) is on today's frontier: nothing is both smarter and cheaper.
GPT-5.5 (High)GPT-6 Luna (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-5-5-high/gpt-6-luna-medium · Markdown: /api/v1/compare/gpt-5-5-high/gpt-6-luna-medium?format=md · llms.txt · agent skill