According to this standard, there are 14 external costs and 6 internal costs associated with this equation.
“The internal costs variable comprises all sources of internal resources
and costs used for staffing efforts during the time period in question.
Examples of internal costs include the fully loaded salary and benefits of
the recruiting team and fixed costs such as physical infrastructure (talent
acquisition system costs, etc.).”
“The external costs variable comprises all sources of spending outside the
organization on recruiting efforts during the time period in question.
Examples of external costs include third-party agency fees, advertising
costs, job fair costs and travel costs in the course of the recruiting effort.”
Here is a link to additional information for the Cost Per Hire Standard: