GPT-5.1 is the latest frontier-grade model in the GPT-5 series, offering stronger general-purpose reasoning, improved instruction adherence, and a more natural conversational style compared to GPT-5. It uses adaptive reasoning...
OpenAI: GPT-5.1 — OpenAI. Context window 400,000 tokens. API pricing (per 1M tokens): Input $1.25, Output $10. License: Proprietary. LMArena 1,443. GPQA Diamond 87.6%.
| Provider | OpenAI |
|---|---|
| API model ID | openai/gpt-5.1 |
| Tier | Frontier |
| Context window | 400,000 tokens |
| Max output | 128,000 tokens |
| License | Proprietary |
| API pricing (per 1M tokens) · Input | $1.25 |
| API pricing (per 1M tokens) · Output | $10 |
| LMArena | 1,443 (gpt-5.1-high) |
| GPQA Diamond | 87.6% |
LMArena (CC-BY 4.0, best reasoning setting, 2026-10-02) · GPQA Diamond: Epoch AI (CC-BY 4.0)
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