Methodology

How our calculations work

We use the standard amortization formula for fixed-rate installment loans and keep tax, fee and trade-in assumptions editable.

Amount financed

Vehicle price − down payment − rebate − trade-in value + trade-in debt + financed tax + financed fees

The amount financed cannot be lower than zero. Costs paid upfront increase cash due upfront rather than principal.

Monthly payment

M = P × r(1+r)ⁿ ÷ ((1+r)ⁿ − 1)

P is principal, r is APR divided by 12 and expressed as a decimal, and n is the whole number of monthly payments. For 0% APR, principal is divided by that number.

Affordability mode

This mode reverses the payment formula to find supported principal, then solves for a vehicle price after applying the user’s other values.

Taxes and trade-ins

Tax treatment differs by jurisdiction. Users control whether trade-in value and rebates reduce taxable price.

Rounding

The loan term is rounded to a whole number of monthly payments. Calculations retain internal precision, and the final amortization payment is adjusted so the balance ends at zero.

Results are planning estimates, not loan offers or financial, legal or tax advice.