Refinance the loan you have, or estimate payments on one you're about to take out.
Most auto refis charge little or no fee — leave it at $0 unless your lender quotes one. Extending the term lowers the payment but can raise total interest; the note below flags it either way.
Refi mode compares your current loan payment against a new refinanced loan. New-purchase mode estimates payments for a car you haven’t bought yet, based on price, down payment, rate, and term.
New-purchase mode has its own sales tax rate field and applies it to the price minus your trade-in, then rolls it into the loan — so don’t add tax into the vehicle price yourself or it gets counted twice. Refi mode has a separate field for refi fees. Dealer add-ons like doc, title, and registration fees aren’t broken out, so fold those into the vehicle price.
Generally worth exploring if rates have dropped since your original loan, your credit has improved, or you want to shorten or extend your term — but confirm there’s no prepayment penalty on your current loan first.