GPT-5.5 Pro
ModelActiveby OpenAI · family “gpt-pro”
GPT-5.5 Pro is OpenAI’s high-capability model optimized for deep reasoning and accuracy on complex, high-stakes workloads. It features a 1M+ token context window (922K input, 128K output) with support for... (description from the OpenRouter listing)
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Epoch Capabilities Index
162.4 #5 of 268
90% CI 159.2 – 166.6
Released
23 Apr 2026
Context window
1.05M tokens
Max output
128K tokens
Input $ / 1M tokens
$30.0
Output $ / 1M tokens
$180.0
Cached input $ / 1M
Unknown
Each benchmark shown separately with its own source
Benchmark results (5)
| Benchmark | Domain | Score | vs best recorded | Setting | Run | Source |
|---|---|---|---|---|---|---|
| FrontierMath-Tier-4-2025-07-01-Privatesuperseded | math | 39.6% ±7.1 | 83% | high | 23 Apr 2026 | Epoch ↗ |
| ARC-AGI-2 | reasoning | 84.6% | 89% | high | — | External ↗ |
| FrontierMath-2025-02-28-Privatesuperseded | math | 52.4% ±2.9 | 100% | high | 23 Apr 2026 | Epoch ↗ |
| SimpleBench | reasoning | 76.9% | 94% | high | — | External ↗ |
| ARC-AGI | reasoning | 96.5% | 98% | high | — | External ↗ |
Source: Epoch AI Benchmarking Hub (CC BY 4.0). “External” rows are leaderboard results Epoch collects from third parties. Best reported setting per benchmark is shown.
API list price over time
Price history
$ per 1M tokens
6 recorded prices on 4 May 2026 (OpenRouter listing + Internet Archive snapshots); re-read on every data refresh, most recently 11h ago. Steps show when the price changed.
Events
- Model launchMajorOpenAI releases GPT-5.5 ProEpoch AI Benchmarking Hub