What you actually finance
The sticker price is not the amount you borrow. Sales tax, title, registration and dealer fees are added; your down payment and trade-in are subtracted. Anything still owed on the trade-in gets rolled back in.
In most US states the trade-in reduces the taxable amount, so a $3,000 trade-in against a $35,000 car at 7% tax saves $210 in tax on top of the $3,000 itself. Seven states do not allow this — California, Virginia, Hawaii, Kentucky, Maryland, Michigan and Montana tax the full purchase price.
A worked example
Total outlay including down payment and trade-in: $43,604.70 for a car listed at $35,000.
Why long terms cost so much
Dealers quote monthly payments because a longer term always makes the payment look better. It also makes the car cost more and keeps you underwater longer.
| Term | Monthly payment | Total interest |
|---|---|---|
| 36 months | $926.18 | $3,302 |
| 48 months | $717.95 | $4,422 |
| 60 months | $593.41 | $5,565 |
| 72 months | $510.71 | $6,731 |
| 84 months | $451.92 | $7,921 |
Stretching from 60 to 84 months saves $141 a month and costs an extra $2,356 in interest. Worse, cars depreciate roughly 20% in year one and about 15% a year after that, so on an 84-month loan you can owe more than the car is worth for four years or more.
The 20/4/10 rule
- 20% down payment, to get past immediate depreciation.
- 4 years maximum term.
- 10% of gross monthly income as the ceiling for all vehicle costs, including insurance and fuel.
It is conservative, and most buyers break it. But it is a useful test of whether a car is affordable rather than merely financeable.
Getting a better rate
- Get pre-approved before you visit the dealer. A credit union or bank pre-approval gives you a rate to beat and removes financing from the negotiation.
- Negotiate the total price, not the monthly payment. A dealer can hit almost any monthly figure by extending the term.
- Watch for markup on dealer financing. Dealers may add one to two percentage points above the rate the lender approved.
- Check your credit first. The gap between excellent and fair credit is commonly five to eight percentage points on an auto loan.
- Rate-shop within 14 days. Multiple auto loan enquiries in that window count as a single hard pull.
For a general loan without vehicle-specific costs, use the loan calculator. For Indian car loans, the EMI calculator is the better fit.
Frequently asked questions
How much car can I afford?
A common guide is the 20/4/10 rule: 20% down, no more than four years of financing, and total vehicle costs — payment, insurance, fuel and maintenance — under 10% of gross monthly income.
On a $60,000 salary that is roughly $500 a month for everything, which points to a car around $25,000 to $28,000.
Does a trade-in reduce sales tax?
In most US states, yes — tax is charged on the price after the trade-in is deducted. On a $35,000 car with a $3,000 trade-in at 7%, that saves $210.
California, Virginia, Hawaii, Kentucky, Maryland, Michigan and Montana tax the full price regardless.
Is a longer loan term ever worth it?
Occasionally — if the rate is very low, or if the lower payment is genuinely necessary for cash flow and you intend to keep the car well beyond the loan.
Otherwise it costs more and keeps you in negative equity longer. On a $30,000 loan, going from 60 to 84 months adds about $2,350 in interest.
What is negative equity and why does it matter?
Owing more on a car than it is worth. It happens because cars depreciate faster than loans amortise, especially early on and especially with a small down payment.
If you trade in while underwater, the shortfall is added to your next loan — so you are financing two cars and only driving one.
Should I finance through the dealer or my own bank?
Get pre-approved by a credit union or bank first, then let the dealer try to beat it. Dealers sometimes can, because manufacturers subsidise promotional rates.
Pre-approval also stops the conversation drifting to monthly payments, where the term can hide a bad price.