Measure APR
For a simple loan, APR is an annualized cost rate; exact APR calculations follow the applicable lending convention and fee treatment.
Formula: APR depends on periodic interest, fees and the loan balance or amount financed
A calculator can make the arithmetic faster, but the assumptions still matter. Check whether the result is a percentage, currency amount, ratio, or rate before comparing it with another figure.
Use the displayed formula as a quick audit trail when checking a result or explaining it to someone else.