15-Year vs 30-Year Mortgage: Which Saves You More?

The Core Trade-Off

A 15-year mortgage and a 30-year mortgage for the same loan amount differ in two big ways: the monthly payment and the total interest paid over the life of the loan. A 15-year term means higher monthly payments but dramatically less interest paid overall. A 30-year term means lower, more manageable monthly payments but significantly more interest paid over time.

Why the Interest Gap is So Large

Two things work against you on a 30-year loan: you're paying interest for twice as long, and 15-year mortgages typically carry a lower interest rate than 30-year loans of the same size — often by 0.5% to 0.75%, because the lender's risk window is shorter. Combined, these two factors mean the total interest paid on a 30-year loan can be more than double what you'd pay on a 15-year loan for the same principal.

Monthly Payment Comparison

The flip side is monthly affordability. On a $400,000 loan, a 15-year term at a lower rate might carry a monthly payment 60–70% higher than the same loan spread over 30 years. That difference is the real constraint for most buyers — it's not that the 30-year loan is a worse deal, it's that many households simply can't fit the 15-year payment into their monthly budget alongside other expenses.

Run Your Own Numbers

Because the exact gap depends on your loan amount, interest rate, and down payment, the best way to compare is to plug in your real numbers. Use the Mortgage calculator to see the monthly payment and total interest for both terms side by side on your specific loan amount.

When a 15-Year Mortgage Makes Sense

• Your monthly budget comfortably absorbs the higher payment without straining other financial goals like retirement contributions or an emergency fund.
• You want to be mortgage-free well before retirement.
• You value the lower interest rate and the discipline of a faster payoff over investment flexibility.

When a 30-Year Mortgage Makes Sense

• You want lower fixed housing costs and more monthly cash flow for other priorities — investing, saving, or simply financial breathing room.
• You'd rather invest the payment difference elsewhere, where long-term market returns could outpace the interest saved by a 15-year term.
• You want flexibility — a 30-year loan doesn't stop you from making extra principal payments when you can, which can shorten your effective payoff time without locking you into a higher required payment every month.

The Middle Ground: Extra Payments on a 30-Year Loan

A popular hybrid strategy is taking a 30-year mortgage for the payment flexibility, but voluntarily making extra principal payments when cash flow allows. This can shrink your effective term and total interest close to what a 15-year loan would achieve, while keeping the lower required payment as a safety net during tighter months.

Bottom Line

A 15-year mortgage is the more mathematically efficient choice if you can afford the payment — it saves substantial interest and builds equity faster. A 30-year mortgage is the more flexible choice, giving you breathing room and the option to pay extra on your own terms. Neither is universally "better" — it depends on how tight your monthly budget already is.