OpenAI API Cost Calculator
How much does the OpenAI API cost per month?
Across OpenAI's 15 priced models at 200K calls/month, the cheapest is GPT-5 Nano at $52.00 per month, verbosity-adjusted rather than list price. The most expensive, GPT-5.4 Pro, runs $27,504 per month for the identical call shape.
Verified 2026-08-08
Raw dataset: data.json. Data as of August 2026.
Ranked cost — 200K calls/month
| Model | Provider | List monthly | Effective monthly | Verbosity | Rank Δ |
|---|---|---|---|---|---|
| GPT-5 Nanobudgetlegacy | OpenAI | $52.00 | $45.52 | — | — |
| GPT-4o Minibudgetlegacy | OpenAI | $114 | $94.56 | — | — |
| GPT-5.4 Nanobudgetlegacy | OpenAI | $184 | $139 | 0.79× | ▲1 |
| GPT-5.6 Lunabudget | OpenAI | $180 | $154 | — | ▼1 |
| GPT-5 Minibudgetlegacy | OpenAI | $260 | $228 | — | — |
| GPT-5.4 Minimidlegacy | OpenAI | $675 | $578 | — | — |
| o3-Minimidlegacy | OpenAI | $836 | $693 | — | — |
| GPT-5midlegacy | OpenAI | $1,300 | $1,138 | — | — |
| GPT-4.1midlegacy | OpenAI | $1,520 | $1,261 | — | — |
| GPT-5.6 Terramid | OpenAI | $1,800 | $1,541 | — | — |
| GPT-4omidlegacy | OpenAI | $1,900 | $1,576 | — | — |
| GPT-5.4midlegacy | OpenAI | $2,250 | $1,926 | — | — |
| GPT-5.6 Solfrontier | OpenAI | $4,500 | $3,852 | — | — |
| GPT-4 Turbofrontierlegacy | OpenAI | $6,900 | $5,604 | — | — |
| GPT-5.4 Profrontierlegacy | OpenAI | $27,000 | $23,616 | 1.04× | — |
Levers live on OpenAI
Prompt caching — available, guide coming soon
Batch API: up to 50% →Model verbosity: up to 94% →Context trimming: up to 47% →The billing gotcha
OpenAI's usage tiers auto-promote on cumulative spend and account age, not a plan you pick — a new key starts on a low rate-limit tier regardless of the monthly total this calculator projects, so the number below is what you'll pay once you're promoted, not necessarily what you can call today. Batch API halves the price but returns results within 24 hours, not synchronously, so it only helps workloads that can tolerate that delay.
Verbosity movers within OpenAI's lineup
- GPT-5.4 Nano is priced #4 by list rate but #3 once its 0.79× verbosity is billed — $184 list vs $165 effective.