Utilities Center

Guide

How Mortgage Payments and Amortization Work

Learn how monthly mortgage payments are calculated, how amortization splits principal and interest, and what drives total cost.

Open the Mortgage / Amortization Calculator

A mortgage calculator estimates the monthly payment on a home loan and produces an amortization schedule showing how each payment splits between interest and principal over the full term.

The mortgage payment formula

M = P × r × (1+r)ⁿ ÷ ((1+r)ⁿ − 1)

It is the same amortization formula as any loan: P is the loan amount, r is the monthly interest rate, and n is the number of monthly payments (e.g. 360 for a 30-year mortgage). Property taxes and insurance are usually added on top as escrow.

How amortization works

Each fixed payment covers the interest due that month, with the remainder reducing the principal. Because interest is charged on the remaining balance, early payments are interest-heavy and later ones principal-heavy. Over a 30-year term, you build equity slowly at first and faster toward the end.

How to use the calculator

  1. Enter the home loan amount.
  2. Enter the annual interest rate.
  3. Enter the term (e.g. 15, 20, or 30 years).
  4. Read the monthly payment and the full amortization schedule.

Examples

A $300,000 mortgage at 6.5% over 30 years: monthly payment ≈ $1,896 (principal and interest only). In the first month about $1,625 is interest and only $271 is principal. By year 25 the split reverses. Total interest over the term exceeds $380,000 — more than the loan itself.

When a mortgage calculator is useful

  • Estimating monthly payments before house-hunting.
  • Comparing 15- vs 30-year terms.
  • Seeing the effect of a larger down payment or lower rate.
  • Planning extra payments to shorten the term.

Put it into practice

Use the Mortgage / Amortization Calculator right now — free, in your browser, no sign-up required.

Try the Mortgage / Amortization Calculator

More guides

Back to all tools

Related free tools

More free online utilities that pair well with this one — same-category tools for the same task, plus handy extras from other categories.