o3-mini API pricing
Last verified
o3-mini costs $1.10 per million input tokens and $4.40 per million output tokens on OpenAI's first-party API.
Rates
| Token type | $ per million |
|---|---|
| Input | $1.10 |
| Output | $4.40 |
| Cached input | $0.55 |
Output costs 4.0× input. That ratio is what decides whether a workload is expensive: reading a lot is cheap, generating a lot is not. Weight your estimates accordingly.
What it costs to run something
Monthly cost at o3-mini's rates, assuming no caching. Token figures are stated so you can check the arithmetic.
| Workload | Monthly cost |
|---|---|
| Support chatbot 1,000 conversations/month · 2,000 in + 500 out each | $4.40 |
| RAG search 10,000 queries/month · 8,000 in + 400 out each | $106 |
| Bulk extraction 10,000 documents · 3,000 in + 300 out each | $46.20 |
| Coding agent 100 runs/month · 400,000 in + 20,000 out each | $52.80 |
With prompt caching on a stable prefix, the input side of each of these falls toward $0.55 per million — frequently a majority of the bill.
Caching economics for o3-mini
Cached input is billed at $0.55 per million tokens — 0.50× the base input rate. For a workload that resends the same prefix, that is the single largest lever available.
Cache reads are 50% cheaper than fresh input, so repeated prefixes are worth structuring for.
Where it sits, and what's cheaper
Among OpenAI's current models, o3-mini is #9 of 23 by input price (1 = cheapest).
Cheaper models that may do the job — worth testing before you assume you need this tier:
| Model | Input | Output | Saving on input |
|---|---|---|---|
| Grok Build 0.1 | $1.00 | $2.00 | 9% |
| Gemini 3 Flash Preview | $0.50 | $3.00 | 55% |
| GPT-4.1 mini | $0.40 | $1.60 | 64% |
The honest caveat: a cheaper model is only cheaper if it still does the task. Test on your actual workload rather than assuming, and measure quality before you migrate.
Tracking what you actually spend
These are list prices. What you are billed also reflects credits, discounts, caching and batch usage — which is why the number worth watching comes from OpenAI's billing API, not a calculator.
How to track spend across providers · Why billing data is daily
Source
Rates verified 2026-08-05 against OpenAI's pricing documentation. Prices change — if this page is more than a month old, check the source.