Why auto loans went sideways
The average new car loan is now 68+ months. Seven-year and even 84-month loans are widely marketed because they make the monthly payment look manageable — but they also make the total interest cost bigger and leave you upside down (owing more than the car is worth) for most of the loan. The calculator above assumes you already have the loan; it focuses on the one thing you can still control: how fast you escape it.
Extra principal: the cleanest win
Auto loans are simple-interest installment loans, which means every extra dollar to principal directly shrinks future interest charges. On a $21,500 balance at 8.25% over 60 months, the standard payment is ~$438. Adding $100/month extra cuts 11–13 months off the loan and saves ~$1,100 in interest. A paid-off car two years early is also a car you can drive cheaply for many more years, compounding the benefit.
The principal-only payment
Just like with mortgages, specify "apply to principal" when you make an extra payment, either through your lender's online portal or in the memo line of a check. Otherwise, many lenders apply the extra as a forward payment — you won't save interest, just get a one-month vacation from the payment later. Read your loan agreement to confirm there is no prepayment penalty (rare on modern auto loans, but always worth checking).
Negative equity: the hidden trap
Cars depreciate ~20% in the first year, ~50% in five years. If you put less than 20% down and took a 72-month loan, you are almost certainly underwater for the first 3+ years. Extra principal payments are how you close that gap faster. Once you have positive equity, your financial options improve dramatically — you can sell or trade without writing a check, refinance if rates drop, and stop paying for gap insurance.
Refinancing an auto loan
If your credit score has improved since you took the loan, or if general auto rates have dropped, refinancing can be worth it. Credit unions are usually the best source — their auto rates often undercut dealer financing by 2–4 points. Shop the same week (multiple auto inquiries in a 14-day window count as one on your credit report) and focus on the total-cost number, not just the monthly.
Where the car loan sits in payoff priority
Most auto loans land in the middle of the APR stack: higher than mortgages and student loans, lower than credit cards and personal loans. Under the avalanche method, that usually means you kill credit cards first, then attack the auto loan. If your auto APR is above 9–10%, it may outrank some store credit cards too.
After you pay it off — don't replace immediately
The wealth move is to keep the car. Take the payment you were making to the lender and reroute it to your savings account or to the next highest-APR debt. Most Americans replace their cars every 5–7 years whether they need to or not. Keeping a paid-off car for another 3–5 years builds wealth faster than almost any investment strategy.
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For education only. Not financial advice.