GPT-5.1 pricing
OpenAI · list prices as of 2026-09-29
| Input | $1.25 per 1M tokens |
|---|---|
| Output | $10 per 1M tokens |
| Cached input (read) | $0.13 per 1M tokens |
| Batch / async | 50% off |
| Context window | 272K tokens |
| Longest answer | 128K tokens |
What a call costs
| Typical call | Input tokens | Output tokens | Per call | Per month at 1,000 a day |
|---|---|---|---|---|
| Chat reply | 1,000 | 300 | $0.00425 | $127.50 |
| Document summary | 6,000 | 400 | $0.0115 | $345.00 |
| Code change | 3,000 | 1,200 | $0.0158 | $472.50 |
No caching or batch discount. Your own prompt will differ: count it exactly below.
Price your own prompt on GPT-5.1Similarly priced models
- Gemini 2.5 Pro (Google): about the same
- GPT-5 (OpenAI): about the same
- Gemini 3.5 Flash (Google): about the same
- GPT-4.1 (OpenAI): 1.0× more
- o3 (OpenAI): 1.0× more
Questions
How much does GPT-5.1 cost?
GPT-5.1 costs $1.25 per million input tokens and $10 per million output tokens, as of 2026-09-29.
How much is one GPT-5.1 call?
A call with 1,000 input tokens and a 300-token answer costs about $0.00425, or $127.50 a month at 1,000 calls a day.
How big is the GPT-5.1 context window?
272,000 tokens.