Loan Payment Calculator
Estimate the monthly principal-and-interest payment for a fixed-rate amortizing loan, plus total interest and total repayment.
- Free to use
- Runs in your browser
- Level B · Industry formula
- Last reviewed 2026-08-16
Loan payment formula
M = P × r ÷ (1 − (1 + r)−n)For a standard fixed-rate amortizing loan, P is principal, r is the monthly interest rate, and n is the number of monthly payments. At 0% interest, the payment is simply principal divided by the number of payments.
What this estimate includes
This calculator estimates principal and interest only. Actual loan or mortgage payments may also include fees, taxes, insurance, mortgage insurance, or other charges depending on the product.
How amortization works
With a typical amortizing loan, each payment is split between interest and principal. Early payments generally contain more interest because the outstanding balance is higher; over time, more of the fixed payment goes toward principal.
Sources & methodology
The calculation uses the standard fixed-rate amortization formula. The Consumer Financial Protection Bureau explains that most mortgage lenders use a standard mathematical formula to calculate principal-and-interest payments and describes how amortization allocates payments between principal and interest over time.
Important note
This tool is for general estimation and education. It does not provide a loan offer, APR disclosure, or financial advice, and it does not account for lender-specific fees or payment rules.
Calculator guide
About the Loan Payment Calculator
Loan payment calculations spread principal and interest across a fixed number of periodic payments.
What to keep in mind
- The stated interest rate and payment frequency must match the loan terms.
- Fees, taxes, insurance, and variable rates may not be included.
- A lower payment can still mean more total interest when the term is longer.
Formula & methodology
Estimate fixed monthly principal-and-interest payments, total interest, and total repayment for an amortizing loan.
Review standard: Level B · Industry formula. How calculator reviews work.CalculateMeasure performs the arithmetic locally in your browser. The displayed result depends on the values and units you enter.
Frequently asked questions
What does this calculator calculate?
Loan payment calculations spread principal and interest across a fixed number of periodic payments.
Can I use the result for an important decision?
Use the result as a calculation aid and verify the inputs, assumptions, and applicable professional or regulatory requirements before relying on it for an important decision.
Does CalculateMeasure store the values I enter?
This calculator performs its arithmetic in your browser. The calculator itself does not need to send your entered values to a server to produce the result.