gpt-5.1 pricing
gpt-5.1 from OpenAI costs $1.25 per 1M input tokens and $10.00 per 1M output tokens. Cached input is $0.125 per 1M. Context window 400,000 tokens.
API id gpt-5.1 · OpenAI · source · updated 2026-08-11
$1.25
Input / 1M tokens
$10.00
Output / 1M tokens
$0.125
Cached input / 1M
400K
Context window
What gpt-5.1 costs in practice
| Workload | Input tokens | Output tokens | Estimated cost |
|---|---|---|---|
| Short chat turn | 1,000 | 500 | $0.0063 |
| Document summary | 50,000 | 2,000 | $0.08 |
| 1M tokens in, 200K out | 1,000,000 | 200,000 | $3.25 |
Estimates use the standard tier and ignore caching discounts, so real bills with repeated prompt prefixes are typically lower.
Common questions
- How much does gpt-5.1 cost per 1M tokens?
- gpt-5.1 costs $1.25 per 1M input tokens and $10.00 per 1M output tokens on the standard tier. Cached input is $0.125 per 1M.
- What is gpt-5.1's context window?
- gpt-5.1 accepts up to 400,000 tokens in a single request, and can return up to 128,000 output tokens.
- Is there a cheaper OpenAI model than gpt-5.1?
- Yes. gpt-4o-mini-2024-07-18 is $0.300 per 1M input tokens versus $1.25 for gpt-5.1, with a 128,000 token context window.
- Where does this gpt-5.1 price come from?
- Directly from OpenAI's published pricing page, re-read every day and normalized to USD per 1,000,000 tokens.