The monthly estimate covers principal and interest only. A lender's actual payment may also include fees, insurance, taxes, or other charges.
How amortization works
An amortizing loan is repaid through scheduled payments that cover both interest and principal. Interest is calculated from the outstanding balance, so early payments usually contain more interest and less principal.
As the balance falls, less interest accrues. More of the same fixed payment can then reduce principal until the balance reaches zero at the end of the term.
How to compare loan scenarios
Monthly payment is only one part of borrowing cost. A longer term usually lowers the required monthly payment but can increase total interest because the balance remains outstanding for more time.
Compare offers using the same loan amount and term. Then examine the rate, fees, total repayment, and whether the rate can change.
- Check whether the quoted rate is fixed or variable.
- Ask which fees are paid upfront and which are financed.
- Confirm whether early repayment carries a charge.
- For mortgages, add taxes, insurance, and association costs separately.
Important limits
This tool models a simple fixed-rate, fully amortizing loan with monthly payments. It does not model adjustable rates, balloon payments, interest-only periods, irregular payment schedules, late fees, or additional principal payments.
The calculated payment is not a loan offer and does not reflect eligibility, credit assessment, or local consumer-credit rules.
The formula used
Payment = P × [i(1 + i)^n] ÷ [(1 + i)^n − 1]P is the amount borrowed, i is the monthly interest rate (annual rate ÷ 12), and n is the number of monthly payments. At 0% interest, principal is divided evenly across the months.
Example: a five-year fixed-rate loan
Borrow $25,000 for five years at a 7.5% annual interest rate. With 60 equal monthly principal-and-interest payments, the estimate is about $500.95 per month. Total repayment is about $30,057, including roughly $5,057 in interest. Origination fees and optional products would increase the effective cost.
Sources and further reading
We use primary educational sources to check terminology and explain how the calculation fits into real financial decisions.
Consumer Financial Protection Bureau — How monthly mortgage payments are calculated↗Consumer Financial Protection Bureau — How amortization affects an auto loan↗