Mortgage payment on $400,000 at 5%
Estimated monthly payment for a $400,000 home at 5% interest, with 20% down over 30 years.
Different price, rate, or down payment? Use the full mortgage calculator for your exact numbers.
About this mortgage calculator
A mortgage is an amortizing loan, which means each fixed monthly payment covers a mix of interest and principal that shifts over time — early payments are mostly interest, and later payments are mostly principal. This calculator uses the standard amortization formula that lenders themselves use to price a fixed-rate loan: it takes your loan amount (home price minus down payment), your annual interest rate, and your loan term in years, and solves for the level monthly payment that pays the loan down to zero by the final payment.
The math behind it converts your annual rate to a monthly rate, raises it to the power of your total number of payments, and balances that against your principal so that every payment is identical in size even though the interest and principal portions inside it change every month. This is exactly how 15-year and 30-year fixed mortgages are structured in the United States, and it's the same formula behind the amortization schedule a lender or mortgage servicer would hand you at closing.
Your down payment matters more than most buyers expect. A larger down payment shrinks your loan amount directly, which lowers both your monthly payment and your total interest paid over the life of the loan — sometimes by tens of thousands of dollars on a 30-year term. Conventional loans typically require at least 20% down to avoid private mortgage insurance (PMI), though many loan programs allow considerably less, especially for first-time buyers.
Mortgage rates have swung dramatically over the decades — from the double-digit rates of the early 1980s down to historic lows near 3% during 2020–2021, before rising again in recent years. Even a one-percentage-point difference in rate can change a 30-year mortgage's total interest by tens of thousands of dollars, which is why comparing rate offers from multiple lenders is one of the highest-value things a homebuyer can do.
This calculator is an estimate for informational purposes only. It shows principal and interest based on the numbers you enter, but a real monthly mortgage payment usually also includes property taxes, homeowners insurance, PMI (if applicable), and sometimes HOA dues — all of which vary by location and lender. Actual rates, terms, and approval depend on your credit profile, income, debt-to-income ratio, and the specific lender, so treat these numbers as a starting point for budgeting, not a loan offer.
Mortgage calculator questions
How mortgage payments and amortization work.
How is my monthly mortgage payment calculated?
This calculator uses the standard fixed-rate amortization formula: your loan amount (home price minus down payment) is spread across equal monthly payments over your loan term, using your annual interest rate converted to a monthly rate, so the loan balance reaches zero on the final payment.
Does this include property taxes, insurance, or PMI?
No. This calculator shows principal and interest only. Your actual monthly housing payment will typically be higher once property taxes, homeowners insurance, private mortgage insurance (if your down payment is under 20%), and any HOA dues are added.
How much difference does a bigger down payment make?
A larger down payment directly reduces your loan amount, which lowers both your monthly payment and the total interest you pay over the life of the loan. Putting down 20% instead of 5% on the same home price can save tens of thousands of dollars in interest over a 30-year term.
Why do I need 20% down to avoid PMI?
Conventional lenders generally require private mortgage insurance when your down payment is below 20% of the home price, because a smaller down payment represents more risk to the lender. PMI is an added monthly cost that isn't included in this calculator's payment figure.
Should I choose a 15-year or 30-year mortgage?
A 15-year term has a higher monthly payment but a much lower total interest cost, since the loan is paid off in half the time and less interest accrues. A 30-year term has a lower, more manageable monthly payment but costs more in total interest. Try both terms in the calculator to compare.
How much does the interest rate really matter?
A lot. Even a single percentage point of difference in rate can change the total interest on a 30-year mortgage by tens of thousands of dollars, which is why shopping and comparing rate quotes from multiple lenders is worthwhile before you commit.
Is this calculator's result exactly what a lender will offer me?
No — it's an estimate for informational purposes. Actual rates, approval, and terms depend on your credit score, income, debt-to-income ratio, the property, and the specific lender. Use this tool to understand the math and budget, then get a real quote from a lender for exact figures.
What happens if I enter a 0% interest rate?
The calculator falls back to a simple even split of the loan amount across your term's total number of payments, since the amortization formula divides by zero when the rate is zero. This is mainly useful for modeling family loans or other zero-interest arrangements.