GPT-5.5-Pro vs GPT-5.6 Luna
OpenAI GPT-5.5-Pro | OpenAI GPT-5.6 Luna | |
|---|---|---|
| Overview | ||
| Company | OpenAI | OpenAI |
| Release date | Apr 23 2026 | Jun 26 2026 |
| Access | Proprietary | Proprietary |
| Benchmarks | ||
Nonsense detection BullshitBench v2Given a confidently-worded but nonsensical prompt, does the AI spot that it makes no sense and push back — instead of playing along and inventing an answer? The score is how often it clearly called out the nonsense. Higher is better. | 36% | — |
Web browsing BrowseCompCan the AI browse the web and track down hard-to-find answers? Higher is better. | 90.1% | — |
Advanced math FrontierMath · Tier 1–3Very hard, research-level math problems. Tiers 1–3 are the (still extremely difficult) lower tiers. Higher is better. | 52.4% | — |
Advanced math FrontierMath · Tier 4Very hard, research-level math problems. Tier 4 is the hardest — close to what professional research mathematicians tackle. Higher is better. | 39.6% | — |
Knowledge work GDPval (win/tie rate)How often the AI's work matches or beats a human expert's on real knowledge-work tasks. Higher is better. | 82.3% | — |
| Timeline | ||
| Release gap | GPT-5.5-Pro shipped 64 days before GPT-5.6 Luna | |
Which is better: GPT-5.5-Pro or GPT-5.6 Luna?
GPT-5.5-Pro and GPT-5.6 Luna don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. GPT-5.5-Pro shipped 64 days before GPT-5.6 Luna, so benchmark comparisons should account for the intervening progress.
Published specifications for these two models are limited — see each model page for the latest details.
Direct benchmark comparisons are unavailable — GPT-5.5-Pro and GPT-5.6 Luna don't publish scores on any of the same benchmarks.
Frequently asked questions
GPT-5.5-Pro was released by OpenAI on Apr 23 2026.
GPT-5.6 Luna was released by OpenAI on Jun 26 2026.
Other comparisons
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