How to Calculate Total Principal Paid on a Car Loan

If you want to know how much principal you've paid on your car, it's easiest and most accurate to contact the financing company and ask for a payoff amount. However, keeping track of it yourself by setting up an amortization table is a good idea. You can see where your money is going each month, see how much you're really paying for your car and quickly determine the payoff amount.

Instructions

1. Determine the total amount that your financed with the loan. Add the purchase price, title transfer fees, taxes, registration and other fees. Subtract the down payment and trade in values.

2. Create an amortization table to determine the interest and principal paid for each month to the current month. It's easiest to do this in Excel or other spreadsheet software, but can also be done manually with a calculator. Label the table with the following column headings: "payment date," "payment amount," "interest paid," "principal paid" and "balance."

3. Start with the first payment date, and populate each row until you get to the current date. Enter your monthly payment in the "payment" column. The payment will always be the same, unless you've paid more than the minimum in some months.

4. Calculate the monthly interest rate. For simple interest, this is the annual interest rate divided by 12.

5. Fill in the first "interest paid" field by multiplying the total amount financed by the monthly interest rate. Subtract the "interest paid" field from the "payment" field. This yields the amount in principal paid for the first month. Subtract the "principal paid" amount from the total cost. The result is the current balance.

6. Continue populating the fields until you get to the current month. For each "interest paid" field, multiply the periodic interest rate by the prior month's balance. Subtract the "interest paid" amount from the "payment" amount to get the new principal paid for that month.