Mortgage Calculator
Work out your monthly mortgage payment before you talk to a lender. Enter the home price, your down payment, the interest rate and the term — the calculator shows your payment, the loan amount and the total interest over the life of the mortgage.
How to use this calculator
- Enter the home price you're considering.
- Enter your down payment as a percentage — 20% avoids mortgage insurance in most markets.
- Enter the interest rate quoted by your lender and choose the term.
- Press Calculate and compare 15-year vs 30-year totals — the interest difference is usually striking.
Formula used
Where M is the monthly payment, L is the loan amount (price − down payment), i is the monthly rate, and N is the term in months. This covers principal and interest; taxes and insurance are billed separately.
Example calculation
A 400,000 home with 20% down at 6.5% for 30 years:
Loan = 320,000 → payment = 2,023/month. Total interest over 30 years = 408,142 — more than the loan amount. The same loan over 15 years costs 2,788/month but only about 181,800 in interest.
How does a mortgage payment work?
A mortgage is a long-term amortizing loan secured by the property itself. Your fixed monthly payment is split between interest on the remaining balance and repayment of principal. In year one of a 30-year mortgage, roughly two-thirds of each payment is interest; by the final years, almost all of it is principal.
Your down payment determines the loan size and often the rate you're offered — larger down payments mean lower risk for the lender. The term is the other big lever: shorter terms carry higher monthly payments but far lower lifetime interest.
Why use this calculator?
- Set a realistic budget before house-hunting instead of anchoring on the lender's maximum approval.
- See exactly how a bigger down payment or a shorter term changes both your monthly payment and lifetime interest.
- Sanity-check any lender's quote — the formula here is the same one they use.
Frequently asked questions
How much house can I afford?
A common guideline is that your total housing cost (payment + taxes + insurance) should stay under 28% of gross monthly income, and total debt payments under 36%. Work backwards: find the monthly payment that fits that budget, then use the calculator to find the matching price.
Is a 15-year or 30-year mortgage better?
A 15-year term typically saves more than half the total interest and often gets a lower rate, but the payment is significantly higher. A 30-year term maximizes flexibility — you can always pay extra toward principal to finish early without being locked into the higher payment.
What is included in a monthly mortgage payment?
This calculator shows principal and interest (P&I). Real payments often also include property tax and homeowners insurance held in escrow (PITI), plus mortgage insurance if your down payment is under 20% and any HOA fees.
How much down payment do I need?
Requirements vary by country and loan type — from around 3% for some first-time-buyer programs up to 20%+ for the best terms. Putting down 20% typically eliminates private mortgage insurance and lowers your monthly cost.