Auto Loan Amortization: Balance, Interest, and Payoff Timing

How an amortizing auto loan works

In an amortizing auto loan, each scheduled payment is divided between finance cost and principal. Early payments generally devote a larger share to interest because the outstanding balance is higher. As the balance falls, more of a level payment can reduce principal.

Source: Consumer Financial Protection Bureau

Simple interest and payment timing

With a simple-interest auto loan, interest is calculated from the outstanding balance on a daily or monthly basis. Paying earlier or adding principal can reduce the balance sooner, while late payment can allow more interest to accrue. The retail installment contract explains the method used.

Payment application order

A payment may be applied to due fees first, then accrued interest, with the remainder applied to principal. This means an amount above the scheduled payment does not automatically produce the expected result unless it is credited as principal under the contract and servicer process.

Source: Consumer Financial Protection Bureau

Read the federal lending disclosures

The Truth in Lending disclosure identifies the annual percentage rate, finance charge, amount financed, total of payments, and payment schedule. APR includes the interest rate and certain mandatory fees, so it is not necessarily identical to the note rate.

Model an early payoff safely

Use the current principal balance and the lender's payoff quote rather than relying only on the original schedule. A payoff quote can include interest accrued through a specific date and permitted charges that a simplified table does not model.

Source: Consumer Financial Protection Bureau