Cost per API Call
Definition
Measures the average cost for each API call made to AI services. This KPI helps track the efficiency of managed AI services like AWS SageMaker or Google Vertex AI.
Formula, as published
Cost Per API Call = Total API Costs / Number of API Calls
- Data sources:
- API usage reports Dashboards from AI platforms Logs from AI platforms Cloud billing data
- Example:
- If the total API costs are $1,200 and the number of API calls made is 240,000, the cost per API call is: $1,200/240,000 = $0.005 per API call
Calculate it
Example values to start with; replace them with yours.
How to measure it
The same idea as cost per inference, for managed AI services billed per call. Calls that retry count once each, so a rising error rate raises this figure with no change in what users get.
Drop in your OpenAI or Claude usage export and see where the AI spend goes.
From the FinOps Foundation
More Unit Economics KPIs
Definition and formula: Cost per API Call, FinOps KPI library, FinOps Foundation, licensed CC BY 4.0, read 16 Oct 2026. Changed: HTML removed, dashes and British spellings changed, formula split from its data sources and examples. The calculator and the notes are Finitizer’s.
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