GPT-5.5 (High) vs GPT-5.6 Luna (High)
Which is better for the money: GPT-5.5 (High) by OpenAI or GPT-5.6 Luna (High) 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-5.5 (High) scores 4.9 points higher (37.0 vs 32.1) but costs 29× as much to run the benchmark ($3181 vs $108; flagship vs mid-range cost classes). They are not alternatives at one budget: pick GPT-5.5 (High) when you need intelligence above 32.1, and GPT-5.6 Luna (High) when 32.1 is enough.
| Metric | GPT-5.5 (High) | GPT-5.6 Luna (High) | Difference |
|---|---|---|---|
| Intelligence (higher is better) | 37.0 | 32.1 | −13.2% GPT-5.6 Luna (High) is 13.2% less intelligent |
| Total AA cost (lower is better) | $3,181.05 | $108.15 | −96.6% GPT-5.6 Luna (High) is 96.6% cheaper |
| End-to-end time (lower is better) | 39.78s | 16.71s | −58.0% GPT-5.6 Luna (High) is 58.0% faster |
| Price per 1M tokens (in / out) | $5.00 / $30.0 | $0.20 / $1.20 | |
| Input modalities | Text, Image | Text, Image |
GPT-5.6 Luna (High) vs GPT-5.5 (High): 13.2% less intelligence, 96.6% less cost to run the AA benchmark, and 58.0% 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-5.6 Luna (High) is off the frontier: at the same or lower cost, Claude Haiku 5.5 (High) scores 37.80 for $94.1.
GPT-5.5 (High)GPT-5.6 Luna (High)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-5-6-luna-high · Markdown: /api/v1/compare/gpt-5-5-high/gpt-5-6-luna-high?format=md · llms.txt · agent skill