Auto Payment Calculator
Know the payment before you shop
Three numbers decide what you pay each month: the amount financed, the rate, and the term. Understand how they pull against each other and you will never be surprised at the finance desk.
The three levers
Move any one of them and the payment moves. Two of the three also change what the car costs you in total.
Term
A longer term lowers the payment and raises total interest. Going from 60 to 72 months on $30,000 saves about $60 a month and costs roughly $700 more overall.
Rate
One percentage point on a $30,000 loan over 60 months is about $14 a month. Small on a statement, roughly $840 across the life of the loan.
Down payment
Every $1,000 down removes about $18 from a 60-month payment and reduces the interest you pay on the rest. It also protects you from owing more than the car is worth.
A worked example
A $34,000 new vehicle with $4,000 down, financing $30,000 at 4.09% APR. Only the term changes across these rows.
Rates current as of July 2026 and subject to change. Membership eligibility required. This is a demonstration website; rates, products, and figures shown are illustrative only.
Getting a number you can trust
Most payment estimates are wrong because they leave out the parts of the deal that are not the sticker price.
Start with the out-the-door price
Add sales tax, title, registration, and any documentation fee to the negotiated price. That total is what you actually finance.
Subtract cash and trade equity
Down payment plus the value of your trade, minus anything you still owe on it. Negative equity gets added back in.
Use a real rate
Pre-qualify to get your actual APR instead of guessing. A soft pull takes two minutes and does not affect your score.
Test two terms
Run the shortest term you can afford next to the one the dealer suggests, and compare total interest rather than monthly payment.
Common questions
Is the calculator's number a loan offer?
No. It is an estimate based on the figures you enter. Your actual rate and payment come from a credit decision, which you can start with a soft pull.
Should I include sales tax in the amount financed?
If you plan to roll it into the loan, yes. Tax varies from roughly 0% to 9% depending on your state, so leaving it out can understate the payment by $40 or more.
How much should I put down?
Ten to twenty percent on a new vehicle keeps you from being underwater during the first two years, when depreciation is steepest. On a used car, less is usually fine.
What percentage of my income should the payment be?
A common guideline is keeping all vehicle costs, including insurance, fuel, and maintenance, under 15% of take-home pay. The loan payment alone is usually 8% to 10%.
Does making extra payments help?
Yes. Our auto loans use simple daily interest with no prepayment penalty, so an extra $50 a month on a 60-month loan typically retires it four to five months early.
Why is my dealer quote higher than this estimate?
Usually add-ons. Extended warranties, protection packages, and dealer markup on the rate all get folded into the payment. Ask for the amount financed and the APR in writing.
Trade the estimate for a real rate
Pre-qualification takes about two minutes and shows you the exact payment you would have with Summit.