Auto / THE DECISION DESK
Auto Loan Calculator
See the payment on a car loan, what each extra year of term really costs in interest, and how long you would owe more than the car is worth.
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$612.38
Financing $31,000 at 6.9% over 5 years. Total interest $5,743.
What it costs
Payment by term
What you owe against what it is worth
The loan line stays below the value line for the whole term — you could sell at any point and clear the loan.
View as table
| Months owned | Loan balance | Car value |
|---|---|---|
| 0 mo | $31,000 | $38,000 |
| 1 mo | $30,566 | $37,452 |
| 2 mo | $30,129 | $36,912 |
| 3 mo | $29,690 | $36,379 |
| 4 mo | $29,248 | $35,854 |
| 5 mo | $28,804 | $35,337 |
| 6 mo | $28,358 | $34,828 |
| 7 mo | $27,908 | $34,325 |
| 8 mo | $27,456 | $33,830 |
| 9 mo | $27,002 | $33,342 |
| 10 mo | $26,545 | $32,861 |
| 11 mo | $26,085 | $32,387 |
| 1 yr | $25,623 | $31,920 |
| 1 yr 1 mo | $25,157 | $31,460 |
| 1 yr 2 mo | $24,690 | $31,006 |
| 1 yr 3 mo | $24,219 | $30,559 |
| 1 yr 4 mo | $23,746 | $30,118 |
| 1 yr 5 mo | $23,270 | $29,683 |
| 1 yr 6 mo | $22,792 | $29,255 |
| 1 yr 7 mo | $22,311 | $28,833 |
| 1 yr 8 mo | $21,826 | $28,417 |
| 1 yr 9 mo | $21,340 | $28,007 |
| 1 yr 10 mo | $20,850 | $27,603 |
| 1 yr 11 mo | $20,357 | $27,205 |
| 2 yr | $19,862 | $26,813 |
| 2 yr 1 mo | $19,364 | $26,426 |
| 2 yr 2 mo | $18,863 | $26,045 |
| 2 yr 3 mo | $18,359 | $25,669 |
| 2 yr 4 mo | $17,852 | $25,299 |
| 2 yr 5 mo | $17,342 | $24,934 |
| 2 yr 6 mo | $16,830 | $24,574 |
| 2 yr 7 mo | $16,314 | $24,220 |
| 2 yr 8 mo | $15,796 | $23,871 |
| 2 yr 9 mo | $15,274 | $23,526 |
| 2 yr 10 mo | $14,749 | $23,187 |
| 2 yr 11 mo | $14,222 | $22,852 |
| 3 yr | $13,691 | $22,523 |
| 3 yr 1 mo | $13,158 | $22,198 |
| 3 yr 2 mo | $12,621 | $21,878 |
| 3 yr 3 mo | $12,081 | $21,562 |
| 3 yr 4 mo | $11,538 | $21,251 |
| 3 yr 5 mo | $10,992 | $20,945 |
| 3 yr 6 mo | $10,443 | $20,642 |
| 3 yr 7 mo | $9,891 | $20,345 |
| 3 yr 8 mo | $9,335 | $20,051 |
| 3 yr 9 mo | $8,777 | $19,762 |
| 3 yr 10 mo | $8,215 | $19,477 |
| 3 yr 11 mo | $7,649 | $19,196 |
| 4 yr | $7,081 | $18,919 |
| 4 yr 1 mo | $6,509 | $18,646 |
| 4 yr 2 mo | $5,934 | $18,377 |
| 4 yr 3 mo | $5,356 | $18,112 |
| 4 yr 4 mo | $4,775 | $17,851 |
| 4 yr 5 mo | $4,190 | $17,593 |
| 4 yr 6 mo | $3,601 | $17,340 |
| 4 yr 7 mo | $3,010 | $17,090 |
| 4 yr 8 mo | $2,415 | $16,843 |
| 4 yr 9 mo | $1,816 | $16,600 |
| 4 yr 10 mo | $1,214 | $16,361 |
| 4 yr 11 mo | $609 | $16,125 |
| 5 yr | $0 | $15,892 |
How this is calculated
The payment comes from the standard amortization formula, where P is the amount financed, r the monthly rate, and n the number of payments:
payment = P × r / (1 − (1 + r)−n)
Amount financed is the price less your down payment and net trade-in. The term table reruns that same formula at 36, 48, 60, 72 and 84 months so the tradeoff is visible in one place rather than requiring five separate calculations.
Depreciation is modelled as a constant annual percentage, compounded monthly. Real depreciation is front-loaded — a new car loses a large share of its value the moment it is registered — so the first months here are slightly optimistic and the underwater period is, if anything, understated.
The underwater count compares the remaining loan balance against the depreciated value at every month of the term, and reports how many of those months you owe more than the car is worth.
Not modelled: sales tax, registration, dealer fees, gap insurance premiums, or the higher comprehensive coverage a lender typically requires. Enter the out-the-door price rather than the sticker price to capture most of these.
Common questions
›Is a 72 or 84 month car loan a bad idea?
Not automatically, but it changes what you are buying. A longer term lowers the payment and raises total interest, and it keeps you underwater — owing more than the car is worth — for far longer. The practical risk is not the interest, it is being unable to sell or trade the car for years without writing a cheque to close the gap. If a long term is the only way the payment fits, that is usually a signal the car is too expensive rather than that the term is too short.
›What does 'underwater' actually mean here?
Your loan balance is higher than what the car would sell for. It happens because cars depreciate fastest in the first year or two while the early payments on a loan go mostly to interest. If the car is written off in that window, a standard insurance policy pays the car's value, not your loan balance, and you owe the difference out of pocket. Gap insurance exists specifically to cover that shortfall.
›Should I put my trade-in toward the down payment?
Enter it as trade-in value net of anything you still owe on that car. If you owe more than it is worth, the difference is usually rolled into the new loan, which starts the new car underwater from day one and makes the situation worse rather than better. In that case the honest entry here is a negative trade-in, or simply keeping the old car until the balance clears.
›Does the calculator include tax, title and fees?
No. Enter the out-the-door price if you want those included, since sales tax and registration are commonly financed alongside the car and materially change both the payment and how long you stay underwater. Dealer add-ons like extended warranties and paint protection are also financed at the loan rate, which is why they cost considerably more than their sticker price.
›Is dealer financing or a bank loan better?
Get a rate from your own bank or credit union before visiting the dealer, then treat the dealer's offer as a competing quote. Manufacturer promotional rates can genuinely beat a bank, but they are often tied to forgoing a cash rebate — run both scenarios here, once with the low rate and full price, once with the higher rate and the price reduced by the rebate.