**How to Calculate APR: Acronym for Annual Percentage Rate. The Effective Annual Interest Rate. The actual amount of interest for each year. You should be able to get a basic understanding from Wikipedia for Annual Percentage Rate and Nominal Interest Rate.
You will have to be sure you are using the right interest rate so that the calculations are correct for your situation. You can convert using the Effective Annual Interest Rate Calculator or Nominal Interest Rate Calculator. See the following explanation.
A loan with a Nominal Interest Rate of 7% compounded monthly will have a higher Effective Annual Interest Rate than a loan with an APR of 7% compounded monthly.
Note: This calculator will compute an auto loan's effective monthly interest rate, monthly payments, total number of payments, total paid on the loan, total interest paid on the loan and interest as a percentage of the principal loan amount based on the cost of the auto, the APR and the term of the loan in months.