About the GAP Insurance Calculator
This GAP insurance calculator shows how much more you could owe on your auto loan than the car is worth if it were totaled or stolen. Standard auto insurance pays the car’s actual cash value, not your loan balance, so in the early years of a loan you can be left owing thousands on a car you no longer have. Guaranteed Asset Protection (GAP) coverage pays that difference.
Enter the price, your down payment, anything rolled into the loan (sales tax, fees, negative equity from a trade-in), the APR and term, and how quickly the car loses value. The calculator projects the loan balance and the car’s value every month and reports the biggest gap, when it occurs and how long you stay “upside down”. Compare that with the GAP price you were quoted to judge whether it is worth buying.
GAP matters most with small down payments, long terms (72–84 months), high rates, rolled-in negative equity and fast-depreciating models. Depreciation is modelled as a steeper first year followed by a steady yearly rate; real values vary by model and market. GAP from your car insurer is often much cheaper than the dealer’s price, and policies differ on whether they cover your deductible.
With the default inputs, the largest gap (loan − car value) is $1,768.96. Change any value above to recalculate instantly.
How to use the gap insurance calculator
- 1Enter the vehicle price, down payment and anything rolled into the loan.
- 2Enter the loan APR and term.
- 3Set realistic depreciation rates for your model.
- 4Enter the GAP price you were quoted.
- 5Check the largest gap, how long it lasts and the verdict, then compare quotes from your insurer.
Formula and method
The amount financed is the price minus your down payment plus anything rolled in (tax, fees, negative equity). The loan balance is projected month by month with the standard amortization formula: each month interest at APR ÷ 12 is added and the fixed payment is subtracted.
The car’s value starts at the purchase price and falls smoothly at the first-year depreciation rate for 12 months, then at the later yearly rate. The gap is balance minus value each month; the largest positive gap is roughly what GAP insurance would pay after a total loss (insurer deductibles and policy limits aside). Time upside down counts the months (including the day you buy) in which the balance is above the value.
- Balance(m)
- Loan balance after m payments
- Value(m)
- Estimated actual cash value after m months
- d₁, d₂
- First-year and later yearly depreciation rates
Worked examples
$35,000 car, $3,000 down, 72 months at 7.5%
Rolling $2,500 of tax and fees into the loan means you borrow $34,500 — 98.6% of the price. After a 20% first-year drop the car is worth $28,000 while you still owe about $29,769, a $1,769 gap. You are upside down from month 2 to month 30 (29 months), and the gap is larger than the $600 GAP price, so coverage is reasonable protection — ideally bought cheaply from your insurer.
20% down on a 48-month loan
Borrowing $28,000 (80% of the price) on a 48-month loan keeps the balance below the car’s value from day one, so there is never a gap to insure.
84 months with $5,000 negative equity rolled in
With nothing down and $7,500 of fees and negative equity rolled in, you owe $42,500 on a $35,000 car — $7,500 underwater on day one and about $9,934 after a year as the car depreciates. You stay upside down for 61 months, more than five years, which is exactly when GAP earns its keep.
Frequently asked questions
What does GAP insurance cover?+
GAP (Guaranteed Asset Protection) pays the difference between what your auto insurer pays for a totaled or stolen car — its actual cash value — and the amount you still owe on the loan or lease. Some policies also cover your insurance deductible.
Do I need GAP insurance?+
It is most useful if you put less than about 20% down, chose a loan of 60 months or longer, rolled negative equity into the loan, or bought a model that depreciates quickly. If your loan balance is always below the car’s value, you do not need it.
Where is GAP insurance cheapest?+
Adding GAP to your existing car insurance policy often costs only a few dollars a month. Dealer-sold GAP is commonly a one-time charge of several hundred dollars or more and is often rolled into the loan, where you also pay interest on it.
Can I cancel GAP insurance?+
Usually yes. Once you owe less than the car is worth you can cancel, and dealer or lender GAP policies typically refund the unused portion on a pro-rated basis. Check the contract terms.
Do leases include GAP coverage?+
Many leases include GAP or a similar waiver automatically, because lessees are upside down for most of the lease. Check your lease agreement before buying a separate policy.
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.