GPT-5.5 is OpenAI’s frontier model designed for complex professional workloads, building on GPT-5.4 with stronger reasoning, higher reliability, and improved token efficiency on hard tasks. It features a 1M+ token...
OpenAI: GPT-5.5 — OpenAI. Context window 1,050,000 tokens. API pricing (per 1M tokens): Input $5, Output $30. License: Proprietary. LMArena 1,471. GPQA Diamond 90.7%.
| Provider | OpenAI |
|---|---|
| API model ID | openai/gpt-5.5 |
| Tier | Frontier |
| Context window | 1,050,000 tokens |
| Max output | 128,000 tokens |
| License | Proprietary |
| API pricing (per 1M tokens) · Input | $5 |
| API pricing (per 1M tokens) · Output | $30 |
| LMArena | 1,471 (gpt-5.5-high) |
| GPQA Diamond | 90.7% |
LMArena (CC-BY 4.0, best reasoning setting, 2026-10-02) · GPQA Diamond: Epoch AI (CC-BY 4.0)
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