How does an auto loan work?

You borrow a set amount to buy a vehicle, repay it in fixed monthly installments over a term of 24–84 months, and the lender holds the title as collateral until the loan is paid off.

The core mechanics

Your monthly payment covers two things: principal (the amount you borrowed) and interest (the lender's cost for extending credit). Early in the loan, most of each payment goes toward interest. As the balance falls, the interest portion shrinks and more chips away at principal. This is called amortization.

Principal — the purchase price minus your down payment and any trade-in credit.
Interest rate / APR — the annualized cost of borrowing; lenders set this based on your credit profile, loan term, and vehicle type.
Loan term — most new-car loans run 48–72 months; longer terms mean lower payments but more total interest paid.
Down payment — reduces the amount financed and can lower your rate by improving the loan-to-value ratio.

Secured by the vehicle

Auto loans are secured debt — the vehicle is collateral. The lender places a lien on the title, meaning you cannot sell or transfer it free-and-clear until the balance is zero. If you default, the lender can repossess the vehicle. The CFPB explains that your payment is applied first to fees, then to interest, then to principal — so extra payments reduce principal directly and cut total interest owed.

What drives your payment

Loan amount (purchase price − down payment − trade-in)
Interest rate — lower credit scores produce higher rates
Term length — a 72-month loan has a lower monthly payment than a 48-month loan on the same amount, but the total interest paid is higher
New vs. used — used-vehicle loans typically carry higher rates than new-vehicle loans

Data points

The CFPB advises comparing the APR, not just the monthly payment, because a longer term can reduce the monthly amount while significantly increasing total cost. — CFPB — Auto Loans
The Federal Reserve's G.19 release tracks the average amount financed and finance rates for new car loans. — Federal Reserve — G.19 Consumer Credit
The portion of your payment applied to interest decreases over time as the outstanding principal shrinks — making extra payments most valuable early in the loan. — CFPB

Key takeaways

Get pre-approved before visiting a dealership so you have a rate benchmark.
Compare total loan cost (principal + all interest), not just monthly payment.
A larger down payment reduces both the amount financed and often your rate.
Paying extra toward principal early shortens the loan and cuts total interest.