GPT-5.1 API Pricing
GPT-5.1 by OpenAI costs $1.25 per million input tokens and $10.00 per million output tokens.
Price verified from OpenAI's pricing page.
Rates and limits
- Input / 1M
- $1.25
- Output / 1M
- $10.00
- Cached input / 1M
- $0.125
- Batch discount
- 50% off
- Context window
- 400K tokens
- Released
- April 2025
What GPT-5.1 costs per month
Token volume split 3:1 between input and output, with no prompt caching.
| Tokens per month | Input / output | Standard | Batch API |
|---|---|---|---|
| 1M | 750K / 250K | $3.44 | $1.72 |
| 10M | 7.5M / 2.5M | $34.38 | $17.19 |
| 100M | 75M / 25M | $343.75 | $171.88 |
Where to run GPT-5.1
Prices above are OpenAI's direct rates. Cloud platforms can charge differently; the cloud platform view compares them.
- OpenAI APIDirect API
- Azure OpenAI ServiceCloud / platform
- OpenRouterCloud / platform
GPT-5.1 pricing FAQ
How much does GPT-5.1 cost per million tokens?
GPT-5.1 costs $1.25 per million input tokens and $10.00 per million output tokens, as listed on OpenAI's pricing page on September 30, 2026.
How much does GPT-5.1 cost for 10 million tokens a month?
About $34.38 a month, assuming 7.5 million input and 2.5 million output tokens with no prompt caching, or $17.19 through the batch API.
What is the context window of GPT-5.1?
GPT-5.1 accepts up to 400,000 tokens of context.
Does GPT-5.1 support prompt caching?
Yes. Cached input tokens cost $0.125 per million, 90% less than the standard input rate.
Is there a batch discount for GPT-5.1?
Yes. Requests sent through the batch API cost 50% less: $0.625 per million input tokens and $5.00 per million output tokens.
Where can I use the GPT-5.1 API?
GPT-5.1 is available through OpenAI API, Azure OpenAI Service, and OpenRouter.
Compare with other models
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Prices shown as input / output per million tokens. All model prices · Side-by-side comparison