GPT-5.1 pricing
OpenAI ·
gpt-5.1 ·
272K context
· 42nd cheapest of 64 current models
What GPT-5.1 costs
| Rate | Per 1M tokens | Per 1K tokens | What it covers |
|---|---|---|---|
| Input | $1.25 | $0.00125 | Every token you send: prompt, history, documents. |
| Output | $10 | $0.01 | Every token the model generates, including hidden reasoning tokens. |
| Cached input | $0.125 | $0.000125 | Input served from the provider’s prompt cache. |
What that means in practice
The same three workloads are costed on every model page, so these numbers are directly comparable across the catalog. No prompt caching and no batch discount is assumed — the figures are what you pay before you optimise anything.
Support chatbot
2,500 six-turn conversations a day
$6,553 / month
$0.087 per conversation · $79,730 a year
An 800-token system prompt, 400-token questions and 900-token answers, over six turns — each turn re-sending everything before it.
Document summariser
1,000 single-shot summaries a day
$698 / month
$0.023 per conversation · $8,486 a year
One 12,000-token document in, an 800-token summary out, no conversation history. The case where input dominates the bill.
Coding agent
200 twelve-turn sessions a day
$4,185 / month
$0.698 per conversation · $50,918 a year
A 3,000-token system prompt, 1,500-token instructions and 2,500-token responses over twelve turns. Long sessions are where the quadratic cost of re-sent history stops being theoretical.
Change the assumptions in the calculator
Cheaper, and scored at least as capable
Every model below costs less on a blended rate and carries a capability score at least as high as GPT-5.1’s. The score is a rough estimate, not a benchmark — treat it as a shortlist, not a verdict.
| Model | Input | Output | Blended saving | |
|---|---|---|---|---|
| Grok 4.5 | $2 | $6 | 13% | |
| Kimi K2.6 | $0.95 | $4 | 50% | |
| Gemini 3.6 Flash | $1.5 | $7.5 | 13% | |
| Grok 4.3 | $1.25 | $2.5 | 55% | side by side |
| GLM-5.1 | $1.4 | $4.4 | 37% | side by side |
Head to head
Specification
| Context window | 272K tokens |
|---|---|
| Maximum output | 128K tokens |
| Provider | OpenAI |
| Status | Current |
| Reasoning model | Yes |
| Vision | Yes |
| Token counting | Exact, via o200k_base |
Where these numbers come from
Last checked against its source on 2026-08-02, and the published rates last actually moved on 2026-08-02. Source of record: LiteLLM’s community-maintained price map.
Regional and data-residency premiums, priority tiers, server-side tool fees and negotiated discounts are not included. Prices change without notice; this page is rebuilt every time the catalog does.