Mortgage Amortization Schedule Calculator
See exactly how each monthly mortgage payment splits between principal and interest, and track your remaining balance month by month over the life of the loan. Use this when buying a home or reviewing your current mortgage.
About this calculator
A mortgage amortization schedule breaks every payment into two parts: interest owed on the remaining balance and principal reduction. The fixed monthly payment M is calculated using the formula M = P × (r × (1+r)^n) / ((1+r)^n − 1), where P is the loan amount, r is the monthly interest rate (annual rate ÷ 12), and n is the total number of payments (years × 12). In the early years, most of each payment covers interest because the balance is large. As the balance falls, the interest portion shrinks and the principal portion grows — this shift is amortization. By producing the full schedule, the calculator lets you see precisely when you build equity, how much interest you pay in any given year, and the exact payoff date.
How to use
Suppose you borrow $300,000 at 6.5% annual interest for 30 years. First, r = 6.5/100/12 = 0.005417. Then n = 30 × 12 = 360 payments. Monthly payment M = 300,000 × (0.005417 × (1.005417)^360) / ((1.005417)^360 − 1) ≈ $1,896. In month 1, interest = $300,000 × 0.005417 ≈ $1,625, and principal = $1,896 − $1,625 = $271. By month 360 almost the entire $1,896 pays down principal. Total interest paid over 30 years ≈ $382,560.
Frequently asked questions
How does a mortgage amortization schedule show the split between principal and interest each month?
Each month, interest is calculated by multiplying the current outstanding balance by the monthly interest rate (annual rate ÷ 12). The remainder of your fixed payment reduces the principal. Because the balance decreases each month, the interest portion shrinks slightly and the principal portion grows, even though your payment stays the same. This gradual shift is what amortization means — the loan is systematically paid off over time.
Why do I pay so much interest at the beginning of a 30-year mortgage?
At the start of the loan, your outstanding balance is at its highest, so the interest charge each month is at its largest. For a $300,000 loan at 6.5%, the first month's interest alone is about $1,625 out of a $1,896 payment. Over time the balance falls, so interest charges shrink and more of each payment chips away at principal. This front-loaded interest structure is a mathematical consequence of the amortization formula, not a bank fee.
What is the difference between an amortization schedule and a simple mortgage payment calculator?
A basic mortgage calculator tells you only the fixed monthly payment amount. An amortization schedule goes further, showing you the exact interest and principal breakdown for every single payment over the loan's life. It also tracks the remaining balance after each payment, so you can see your equity at any point in time. This detail is useful for tax planning (mortgage interest deductions), refinancing decisions, and understanding when it makes sense to make extra payments.