How the payment is calculated
This is a standard fixed-rate installment loan. The monthly payment is M = P × r(1 + r)^n ÷ ((1 + r)^n − 1), where P is the amount borrowed, r is the annual interest rate divided by 12, and n is the term in months. With a 0% rate, the payment is simply the amount divided by the number of months. The mortgage calculator on this site uses the same calculation; only the inputs are framed differently.
Worked example
Borrowing 20,000 at 6% for 60 months gives a monthly payment of 386.66. Over the full term you pay 23,199.35 in total, of which 3,199.35 is interest.
The amortization schedule
Open the schedule to see how each payment splits between interest and principal. Early payments are mostly interest because the balance is at its highest; the principal share grows each month as the balance falls. Every amount is rounded to the cent, the last payment absorbs any remaining cents so the balance reaches exactly zero, and the totals are summed from those same rows.
Limitations
The calculator assumes a fixed rate, equal monthly payments and no fees. Loans with variable rates, balloon payments, origination fees or extra payments will differ, so treat the result as an estimate rather than a lender's quote.