Mortgage Amortization Calculator
Calculate your monthly payment, see how principal and interest split over time, and export your full amortization schedule.
Loan Parameters
Total Monthly Payment
$2,842.11
Tax + Insurance + HOA + PMI
Total Interest
$459,160
Over 30 years
Total Paid
$1,023,160
56.1% interest
Loan Amount
$360,000
20.0% down
Principal vs. Interest Over Time
How the Mortgage Amortization Calculator Works
NumeraDesk calculates your monthly mortgage payment and builds a complete month-by-month amortization schedule. Enter your home price, down payment, interest rate, and loan term, and the tool instantly shows how every payment is split between principal and interest over the life of the loan.
The Mortgage Payment Formula
The standard fixed-rate mortgage payment is calculated using the following formula:
M = P × r(1 + r)n / ((1 + r)n - 1)- M = Monthly payment
- P = Loan amount (home price minus down payment)
- r = Monthly interest rate (annual rate divided by 12, then by 100)
- n = Total number of payments (loan term in years × 12)
Each month, the interest portion is calculated as the remaining balance multiplied by the monthly rate. The principal portion is the total payment minus the interest portion. As the balance decreases, more of each payment goes toward principal, accelerating your equity growth over time.
Key Mortgage Terms Explained
Principal
The amount you borrow. Each monthly payment reduces this balance, building your equity in the home.
Interest
The cost of borrowing, charged as a percentage of your remaining balance. Higher early in the loan, decreasing over time.
Amortization
The process of paying off a loan through regular, scheduled payments that cover both principal and interest.
Down Payment
The upfront cash you pay toward the home. A larger down payment reduces your loan amount and monthly payment.