About the Negative Equity Calculator
This negative equity calculator shows whether your car loan is “upside down” — you owe more than the car is worth — and what happens if you trade it in and roll the shortfall into the loan on your next vehicle. It compares the new payment with and without the carried-over debt, and projects how many months it will take before the new car is worth more than you owe.
It is built for anyone considering a trade-in while still paying off a car, and for buyers comparing a dealer offer that “pays off your trade no matter what you owe”. That promise usually means the negative equity is added to the new loan, so you pay interest on a car you no longer own.
Enter your current payoff amount and a realistic trade-in value (from a written offer or valuation guide), then the new car’s price, your cash down payment, the rate and term. The equity projection uses a steady yearly depreciation rate; real cars often lose more in the first year. Sales tax and fees are not included.
With the default inputs, the negative equity (owed above value) is $5,000.00. Change any value above to recalculate instantly.
How to use the negative equity calculator
- 1Enter your current loan payoff amount (ask your lender for the 10-day payoff figure).
- 2Enter a realistic trade-in value from a written offer or valuation guide.
- 3Enter the new car price, cash down, APR and term.
- 4Review the negative equity, the extra monthly cost and how long you will be underwater.
- 5Try a larger down payment or shorter term to see how to limit the damage.
Formula and method
Negative equity is the loan payoff minus the car’s trade-in value. When you trade in, that shortfall does not disappear — it is added to the amount you borrow for the next car. The monthly payment on the new loan uses the standard amortization formula M = P × r(1 + r)^n ÷ ((1 + r)^n − 1), with r the monthly rate and n the term in months. Comparing it with the payment on price minus down payment isolates what the old debt costs.
To estimate when you will be right-side up, the calculator steps month by month through the loan balance and compares it with the new car’s value, which declines at a constant yearly depreciation rate: value = price × (1 − d)^(months ÷ 12). Taxes, fees and GAP insurance are excluded.
- P
- New loan principal including rolled-over debt
- r
- Monthly interest rate (APR ÷ 12)
- n
- Loan term in months
- d
- Yearly depreciation rate of the new car
Worked examples
$5,000 underwater, rolled into a 72-month loan
You owe $22,000 on a car worth $17,000, so negative equity is $5,000. The new loan becomes $35,000 − $2,000 + $5,000 = $38,000 (109% of the price). At 7.5% for 72 months the payment is $657.02 instead of $570.57 — $86.45 more each month and $6,224 over the loan. You stay underwater for about 35 months.
Down payment covers the gap
Owing $3,000 more than the trade is worth and putting $3,000 down leaves a $28,000 loan on a $28,000 car. The payment is $553.11 rather than $493.85, so the old loan still costs $3,556 over five years.
Positive equity trade-in
The car is worth $2,000 more than you owe, so that equity reduces the new loan to $28,000. At 8% for 60 months the payment is $567.74, about $40.55 less than borrowing the full price.
Frequently asked questions
What does negative equity on a car mean?+
It means you owe more on your auto loan than the car is worth. If the payoff is $22,000 and the car would sell or trade for $17,000, you have $5,000 of negative equity and are “upside down”.
Can I roll negative equity into a new car loan?+
Many lenders allow it, often up to a loan-to-value limit around 120–125%. But you pay interest on the old debt again, your new payment is higher, and you start the new loan even further underwater.
How do I get out of an upside-down car loan?+
Common options are to keep the car and pay extra principal until the balance falls below its value, pay the difference in cash when you trade, sell privately for more than the trade-in offer, or refinance to a lower rate to build equity faster.
Should I buy GAP insurance if I have negative equity?+
GAP coverage pays the difference between the insurance payout and your loan balance if the car is totalled or stolen. With a high loan-to-value it can prevent owing thousands on a car you no longer have.
Why does a longer loan make negative equity worse?+
A 72- or 84-month loan pays principal down slowly while the car depreciates fastest in its first years, so the balance stays above the value for longer — and you are more likely to carry negative equity into the next trade.
Results are estimates for educational purposes and are not financial advice. Rates, fees and terms vary — confirm with your lender or a licensed advisor before making decisions.