Why is a 30-year mortgage so popular?

Spreading payments over 360 months produces the smallest monthly payment for a given loan amount, which keeps housing costs more manageable on a monthly basis. The trade-off is more total interest over the life of the loan compared to a 15 or 20 year term.

How much more interest does a 30-year term cost versus 15?

Roughly speaking, a 30-year mortgage at the same rate as a 15-year will produce more than double the total interest, because the principal pays down more slowly. The exact figure depends on the interest rate. Enter your numbers and switch the term to compare.

Can I pay extra to shorten a 30-year mortgage?

Yes. Making additional principal payments reduces the loan balance early, which reduces the interest accrued on every subsequent payment. Even small extra payments each month can cut years off the term and save substantial interest.

Is my financial information sent to a server?

All math runs as JavaScript in your browser tab. Nothing you enter is transmitted.

30-Year Mortgage Calculator

Calculate the monthly payment and total interest on a 30-year fixed mortgage. Enter your loan amount, down payment, and interest rate to see the principal and interest payment, plus optional tax and insurance. Compare the lifetime cost of a 30-year term against shorter terms with the same inputs.

Currency

Home price

Down payment

Interest rate (% per year)

Term (years)

Property tax (% per year, optional)

Home insurance ($ per year, optional)

Formula: M = P[r(1+r)^n] / [(1+r)^n - 1], where P = loan amount, r = monthly rate, n = months

How it works

For a 30-year mortgage, the term plugs into the amortization formula M = P[r(1+r)^n] / [(1+r)^n - 1] as n = 360 monthly payments. The same formula then multiplies the monthly payment by 360 to reveal the lifetime cost, and subtracts the original loan amount to show how much of that total is interest. Switching the term to 15 or 20 years instantly recomputes the comparison so you can see the trade-off between monthly cash flow and total interest paid.

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Every calculation runs locally in your browser as JavaScript. No loan amounts, interest rates, or amortization details leave your device at any point. You can check this yourselfin your browser's DevTools Network tab.

Calculations are estimates for informational purposes only. Consult a financial professional for advice.

Frequently asked questions

Why is a 30-year mortgage so popular?: Spreading payments over 360 months produces the smallest monthly payment for a given loan amount, which keeps housing costs more manageable on a monthly basis. The trade-off is more total interest over the life of the loan compared to a 15 or 20 year term.
How much more interest does a 30-year term cost versus 15?: Roughly speaking, a 30-year mortgage at the same rate as a 15-year will produce more than double the total interest, because the principal pays down more slowly. The exact figure depends on the interest rate. Enter your numbers and switch the term to compare.
Can I pay extra to shorten a 30-year mortgage?: Yes. Making additional principal payments reduces the loan balance early, which reduces the interest accrued on every subsequent payment. Even small extra payments each month can cut years off the term and save substantial interest.
Is my financial information sent to a server?: All math runs as JavaScript in your browser tab. Nothing you enter is transmitted.

30-Year Mortgage Calculator

How it works

Processing runs in your browser

Frequently asked questions

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