15-Year vs 30-Year Mortgage: The Real Difference in Cost

The loan term is one of the biggest choices you make after the price. A shorter term means a higher payment but far less interest. A longer one lowers the payment and keeps your budget flexible. Here is what the tradeoff looks like in dollars.

The comparison

Take a $400,000 loan. Shorter terms usually come with a lower interest rate, so for illustration assume 6.50% on a 30-year loan and 5.75% on a 15-year loan:

	30-year at 6.50%	15-year at 5.75%
Monthly principal and interest	$2,528.27	$3,321.64
Total interest over the loan	$510,178	$197,895
Difference in monthly payment		+$793.37

Choosing the 15-year loan raises the payment by about $793 a month and cuts total interest by roughly $312,000. Even at the same 6.50% rate for both terms, the 15-year payment is $3,484.43 and total interest is $227,197, because you pay the principal back twice as fast.

Why the 15-year saves so much

Interest is charged on the balance. A 15-year loan pays the balance down quickly, so each month’s interest charge shrinks sooner, and the loan has half as many months to accumulate interest. On a 30-year loan at 6.5%, the first month’s interest on $400,000 is $2,166.67, which is about 86% of the $2,528.27 payment. See how mortgage interest is calculated for the mechanics.

What the 30-year buys you

• A lower required payment, which can also help you qualify for a larger loan.
• Flexibility. A smaller required payment is easier to carry if income drops or expenses rise.
• Room to invest or save the difference, if you reliably would.

The middle path

You can take a 30-year loan and pay extra when you can. You keep the low required payment as a safety net and still shorten the loan. The extra payment calculator shows how much interest and time an extra amount saves. The main costs of this approach are that the 30-year rate is usually higher than the 15-year rate, and that it takes discipline to keep sending extra payments.

How to choose

1. Check what payment you can comfortably carry, with room left after saving for retirement and an emergency fund.
2. Compare the real rates you are quoted for both terms, not the averages.
3. If the 15-year payment would stretch you, choose the 30-year loan and decide on an extra payment amount you will really make.
4. If you are near retirement or want to be mortgage-free by a certain date, the shorter term has clear appeal.

Use the mortgage calculator to compare terms side by side for your own price, down payment and rate.

Common questions

Can I switch from a 30-year loan to a 15-year loan later?

Not directly. You would refinance into a new 15-year loan, which means closing costs and a new interest rate that depends on the market at that time. Paying extra on your 30-year loan gives you a similar effect without refinancing, and you can stop or slow down if money gets tight.

Is the interest I save worth the higher payment?

The savings are real, but remember the payment difference does not disappear: in the example it is about $793 a month for fifteen years. Compare that with other uses of the money, such as retirement contributions, an emergency fund and paying off higher-rate debt. Build those first if they are missing, then decide how much to put toward the mortgage.

Are there terms other than 15 and 30 years?

Yes. Many lenders offer 10, 20 and 25-year terms, and they fall between the two on payment and total interest. A 20-year loan, for example, often has a payment that is manageable for people who find the 15-year too high and want to avoid the long interest of a 30-year loan. The calculators let you try several terms.

Key takeaways

• A shorter term raises the payment but can cut total interest by more than half.
• The 30-year loan with extra payments gives you flexibility with some of the savings.
• Compare the actual rates you are quoted, and choose the payment you can sustain.