Enter the numbers on a car you're considering to see the real monthly payment, whether it clears the standard affordability rule of thumb, and how it compares to leasing instead.
Your car
The loan
Starting example numbers below; replace them with your own. Trade-in value reduces what you finance the same way a down payment does.
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Varies a lot by state, often $50-$600.
Tax is estimated on the price minus your trade-in credit (most states tax it that way; a few tax the full price, and a handful, Alaska, Delaware, Montana, New Hampshire, Oregon, charge no state sales tax at all). Both are assumed rolled into the loan below; pay them up front instead and just leave them out.
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Average new-car loan today runs about 70 months; average used-car loan about 68.
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Taxes & fees
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Amount financed
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Monthly payment
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Total interest
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Total cost (down payment + all payments)
Can you afford it?
The 20/4/10 rule
A widely used rule of thumb: put at least 20% down, finance it for 4 years or less, and keep total monthly transportation costs, payment plus insurance, maintenance, and fuel, at or under 10% of your gross (pre-tax) monthly income.
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Defaulted to a rough national average (AAA); replace it with your own quotes if you have them.
Loan balance vs. car value
Are you ever underwater on this loan?
What you owe
What the car is worth (estimated)
Car value follows a general, typical depreciation curve (about 16% lost in year one, roughly 15%/year after that), not a prediction for any specific make or model. Move your mouse over the chart to see both numbers at any month.
Worth considering: GAP insurance
Buy vs. lease
What would leasing this car cost instead?
Uses the vehicle price above as the negotiated (capitalized) price. A lease payment is two pieces: a depreciation charge (the value the car is expected to lose over the lease) and a finance charge (rent on the money, based on the money factor).
How this calculator works
The loan math
Standard fixed-rate amortization: interest accrues monthly on the remaining balance (balance × APR ÷ 12), and your payment is the fixed amount that pays the loan to exactly $0 by the last month of the term. Sales tax is estimated on the price minus your trade-in credit, and both tax and title/registration fees are assumed rolled into the loan; it still doesn't account for a dealer doc fee, which also varies a lot by state.
The 20/4/10 rule
A guideline, not a law: Chase and J.D. Power both describe it as a starting point, and a stricter version (20% down, 3-year term, 8% of income) is sometimes recommended for extra safety margin. Both exist because a car is a depreciating asset you're often borrowing against, unlike a home or an index fund.
The lease math
The depreciation-fee-plus-finance-fee formula is the standard way lease payments are actually built, but the residual value shown is an estimate from the general depreciation curve above, not a quote: a leasing company's actual residual depends on the specific model and current demand, and can be higher or lower than this estimate.