Summary
Use this when comparing personal, auto, or other fixed-rate installment loans: see how rate and term change monthly cash flow and total interest — before fees or insurance. For a home purchase with down payment, prefer the Mortgage Calculator.
Calculation details
The calculation assumes a fixed annual rate, equal monthly payments, and no additional fees. Each payment covers interest due that month and reduces remaining principal. Interpret total interest as the premium paid for borrowing under these assumptions only.
Formula
M = P × [r(1 + r)ⁿ] ÷ [(1 + r)ⁿ − 1], where M is the monthly payment, P is the principal, r is the monthly interest rate, and n is the number of monthly payments. At 0% interest, M = P ÷ n.
Worked example
$250,000 loan at 6.5% for 30 years
With 360 monthly payments, the estimated payment is $1,580.17, total repayment is $568,861.22, and total interest is $318,861.22.
How it works
Enter amount borrowed, annual percentage rate, and term in years. The engine validates inputs, converts the annual rate to a monthly rate, and applies standard fixed-rate amortization. Change rate or term one at a time to compare offers.
Frequently asked questions
How is the monthly payment calculated?
The calculator uses the standard fixed-rate amortization formula and assumes equal monthly payments throughout the selected term.
Does the estimate include lender fees or taxes?
No. Origination fees, taxes, insurance, late charges, and other lender costs are not included.
Can I calculate a zero-interest loan?
Yes. When the annual rate is 0%, the principal is divided evenly by the number of monthly payments.
Why can an actual lender payment be different?
Lenders may use different rounding rules, payment dates, compounding conventions, fees, or additional required costs.