Mortgage Calculator
Calculate monthly mortgage payments, total interest, amortization schedule, and loan-to-value ratio. Free, instant, and private.
About This Tool
Buying a home is the largest financial decision most people make. Understanding your monthly payment before signing a mortgage is critical -- not just the principal and interest payment, but the total cost over the life of the loan. This mortgage calculator gives you a complete picture in seconds: monthly payment amount, total interest paid, total cost of the home, and your loan-to-value ratio.
The calculator uses the standard amortization formula used by banks and lenders worldwide. You enter the home price, down payment (as a dollar amount or percentage), annual interest rate, and loan term. The tool then computes a fixed monthly payment using the formula M = P[r(1+r)^n]/[(1+r)^n - 1], where P is the loan principal, r is the monthly interest rate, and n is the total number of payments.
Beyond the basic monthly payment, the tool generates a year-by-year amortization table showing how each year breaks down between principal repayment and interest. In the early years of a mortgage, a surprisingly large portion of each payment goes toward interest rather than reducing the principal. The amortization table makes this visible, helping you understand the true cost structure of your loan.
A stacked bar visualization shows the breakdown of your total home cost at a glance: how much goes to the down payment, how much to principal repayment, and how much to interest over the life of the loan. This visual representation often surprises borrowers -- on a 30-year loan at typical rates, you may pay nearly as much in interest as you borrowed.
The loan-to-value (LTV) ratio is also displayed. LTV is a key metric lenders use to assess risk. An LTV above 80% typically requires private mortgage insurance (PMI), adding to your monthly costs. By adjusting the down payment slider, you can see how different down payment amounts affect your LTV and monthly payment.
How to Use
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1
Enter the home price
Type the purchase price of the property.
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2
Set your down payment
Enter the down payment as a dollar amount or percentage. Toggle between the two using the dropdown.
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3
Enter the interest rate
Type the annual interest rate offered by your lender.
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4
Choose the loan term
Select 15, 20, 25, or 30 years from the dropdown.
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5
Review your results
View monthly payment, total interest, total cost, LTV ratio, cost breakdown, and amortization schedule.
Where Does This Data Come From?
Monthly payments are calculated using the standard fixed-rate mortgage amortization formula: M = P[r(1+r)^n]/[(1+r)^n - 1]. The amortization schedule is computed by iterating month by month, splitting each payment into principal and interest portions. All calculations run in your browser -- no financial data is transmitted to any server.
