Investing
Scaling to a volume
The per-request cost multiplies linearly by the number of requests, and the annual figure is twelve times the monthly one. Nothing compounds in an API bill.
The Formula
monthly cost = cost per request x requests per month
The per-request cost multiplies linearly by the number of requests, and the annual figure is twelve times the monthly one. Nothing compounds in an API bill.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| c | Cost per request | currency | The full cost of one call. |
| n_m | Requests per month | requests | How many calls are made in a month. |
| C_m | Monthly cost | currency | The bill for the month. |
What Each Symbol Means
ccurrency
Cost per request
The full cost of one call.
n_mrequests
Requests per month
How many calls are made in a month.
C_mcurrency
Monthly cost
The bill for the month.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to calculate ai api costs page applies this equation to a concrete case, shows every intermediate step, and names the mistakes that produce a wrong answer even when the algebra is right.
Where This Formula Appears
This equation is the working core of How To Calculate AI API Costs, filed under Finance. Every number the guide produces comes from substituting into this one line.