gpt-5.1 · OpenAI
The $1.25/$10 generation that anchored 2025 budgets, still listed and fully supported.
Last checked Aug 16, 2026. Calculations use the listed base rates; provider-specific tiers, cache writes, batch pricing, and long-context rules may differ. Confirm the current rate at the official provider source.
Input
$1.25
per 1M tokens
Output
$10.00
per 1M tokens
Cached input
$0.125
per 1M tokens
Context window
400K
max output 128K
GPT-5.1 cost calculator
What GPT-5.1 costs per task
| Use case | Input tokens | Output tokens | Cost / request | Monthly @ 1K req/day |
|---|---|---|---|---|
| Customer support chatbot | 3,500 | 350 | $0.005119 | $153.563 |
| RAG / search-augmented answers | 8,000 | 500 | $0.0105 | $315.00 |
| AI coding assistant | 12,000 | 2,000 | $0.0269 | $807.00 |
| Document summarization | 25,000 | 600 | $0.0344 | $1,033.125 |
| Agentic workflow | 40,000 | 1,500 | $0.0358 | $1,072.50 |
| Content generation | 800 | 1,200 | $0.0127 | $381.90 |
| Data extraction & tagging | 2,000 | 250 | $0.00455 | $136.50 |
| Translation | 5,000 | 5,500 | $0.0604 | $1,812.187 |
Assumes each use case's typical cacheable share of input. See full cost scenarios.
Compare with alternatives
| Model | Input /M | Output /M | Context | Chat request* |
|---|---|---|---|---|
| GPT-5.1 | $1.25 | $10.00 | 400K | $0.0108 |
| GPT-5.6 Terracompare | $2.00 | $12.00 | 1.1M | $0.014 |
| Claude Sonnet 5 | $2.00 | $10.00 | 1M | $0.0124 |
| Gemini 3.5 Flash | $1.50 | $9.00 | 1M | $0.0105 |
*4,000 in + 800 out tokens, 50% cached input where available.
Related calculations
FAQ
GPT-5.1 costs $1.25 per 1M input tokens and $10.00 per 1M output tokens, with cached input at $0.125 per 1M tokens. Verified Aug 16, 2026 against https://developers.openai.com/api/docs/pricing.
GPT-5.1 supports a 400,000-token context window with up to 128,000 output tokens per request, tokenized with o200k_base.
At $1.25/M input and $10.00/M output, GPT-5.1 sits below GPT-5.6 Terra ($2.00/M in, $12.00/M out) — see the comparison table for full-workload differences.