15-Year vs. 30-Year Mortgage: Total Interest Compared

Quick answer: In a 15 vs 30 year mortgage comparison, the 15-year loan almost always wins on total interest, often costing less than half as much. The trade-off is a much higher required payment. In the illustrative $300,000 example below, the 15-year saves roughly $245,000 in interest but costs about $586 more every month.

Picking a loan term is one of the biggest money decisions you will make with a mortgage. It sets your monthly payment, your total interest and how much breathing room you have for the next decade or more. The math is simple, and this article walks through it with real numbers.

Already own a home and wonder whether a shorter term or lower rate would help? You can request free mortgage refinance options using the form on this page.

15 vs 30 Year Mortgage: The Numbers Side by Side

These figures are illustrative, not quotes. They assume a $300,000 loan, a 6.00% rate on the 15-year and 6.75% on the 30-year. Shorter terms usually carry lower rates, but the gap changes with the market. Taxes and insurance are extra and about the same on both loans.

30-year fixed at 6.75%

• Monthly principal and interest: about $1,946
• Total interest over the life of the loan: about $400,500
• Total paid back: about $700,500

15-year fixed at 6.00%

• Monthly principal and interest: about $2,532
• Total interest over the life of the loan: about $155,700
• Total paid back: about $455,700

The gap: the 15-year payment is about $586 higher per month, but total interest is about $244,800 lower. Your own numbers will differ with your loan size and rate, so plug them into our early payoff calculator to see your version.

Why the 15-Year Saves So Much Interest

Two forces work together. The rate is usually lower, and you borrow the money for half as long. Interest is charged on your remaining balance each month, so a balance that shrinks faster gets charged less.

Look at the very first payment on each loan:

• 30-year: about $1,688 of the $1,946 payment is interest, so only about $258 reduces your balance.
• 15-year: about $1,500 of the $2,532 payment is interest, so about $1,032 reduces your balance.

That is roughly four times more principal paid in month one. Every dollar of principal you knock out early stops generating interest for the rest of the loan, and that compounding effect is where most of the savings come from.

On a 30-year loan, the first payment sends close to 90 percent of your money to the lender as interest.

The 30-Year With Extra Payments: Flexibility Built In

Here is the middle path many borrowers overlook. Take the 30-year loan, then voluntarily pay the same $2,532 a month you would owe on the 15-year. That means about $586 extra toward principal each month.

On our example, that plan pays off the loan in roughly 16 years and costs about $195,000 in interest. That is about $205,000 less than paying the minimum for 30 years. It is also about $40,000 more than the 15-year loan, mostly because the 30-year rate is higher in this example.

What you get for that $40,000 is insurance. If a job loss, medical bill or repair hits, you can drop back to the $1,946 payment with no penalty and no refinance. A 15-year loan gives you no such escape hatch.

• Fixed extra amount: set an automatic extra principal payment on payment day.
• Windfalls: send part of a bonus or tax refund to principal.
• One extra payment a year: see how one extra mortgage payment a year shortens the loan.
• Biweekly payments: useful for some borrowers, and we break down whether biweekly mortgage payments really save money.

When a 15-Year Mortgage Is the Better Fit

The shorter term is a strong choice when the higher payment fits comfortably, not when it stretches you. It tends to work best if:

• The payment is easy to carry. A common rule of thumb is keeping total housing costs near 28% of gross income, though lenders and households vary.
• You have a full emergency fund. Many people aim for three to six months of expenses before locking in a bigger payment.
• Higher-interest debt is gone. Credit card balances cost far more than a mortgage, so tackle those first with a debt payoff plan.
• You are already saving for retirement. A fast payoff should not come at the expense of long-term savings.
• You want a firm finish line. If you know you will not make optional extra payments, a required shorter term does the discipline for you.

Owning the house outright sooner also frees up hundreds or thousands of dollars a month later. That is especially valuable if you hope to retire or cut back on work.

A 15-year mortgage forces the savings; a 30-year mortgage lets you choose them.

When a 30-Year Mortgage Is the Smarter Base

A lower required payment is not a sign of weakness. It is a risk-management tool. The 30-year often makes more sense when:

• Your income varies. Commission, gig work or seasonal pay makes a fixed higher payment riskier.
• You are still building cash reserves. The lower payment leaves room to save while you grow the cushion.
• You carry other debt. Car loans, student loans or cards may deserve those extra dollars first.
• You want to invest the difference. Whether that wins depends on your mortgage rate and your risk tolerance. We cover the trade-offs in pay off your mortgage early or invest the difference.
• Qualifying is tight. A lower payment can improve your debt-to-income ratio and the loan amount you qualify for.

You can still attack a 30-year loan aggressively. Compare your options in 7 strategies to pay off your mortgage early, and see our mortgage payoff guide for the full picture.

How to Choose: A Four-Step Test

1. Run both payments. Get quotes for each term and add taxes, insurance and any mortgage insurance for the true monthly cost.
2. Stress-test your budget. Could you cover the 15-year payment if your income dropped 10 to 20 percent for a few months? If not, the 30-year is safer.
3. Check your safety net. Confirm emergency savings and retirement contributions are on track before committing extra cash to the house.
4. Decide on discipline. If you reliably send extra money each month, a 30-year plus extra payments gives you both savings and flexibility. If not, the 15-year automates it.

The Consumer Financial Protection Bureau’s owning a home resources can help you compare loan estimates side by side. If you already have a loan, refinancing between terms or lowering your rate is a separate decision, and we compare mortgage recast vs. refinance to help you sort it out. Keep in mind that refinancing carries closing costs, often estimated at a few percent of the loan, so run the break-even math first.

Want to see what lower rate or shorter term you could get? Use the form on this page to see your free refinance and rate options. Our lower your rate page explains what partners can offer.

FAQ: 15-Year vs. 30-Year Mortgages

Is a 15-year mortgage always cheaper overall?

In total interest, almost always, because you borrow for half the time and usually at a lower rate. It is not cheaper month to month, though, and a payment you struggle to make can cost you far more in stress and risk.

Can I start with a 30-year and switch to a 15-year later?

You can refinance into a shorter term, but that means a new loan, new closing costs and a rate based on current markets. Paying extra on your existing 30-year loan gets a similar result without refinancing.

Will paying extra on a 30-year mortgage hurt me?

Generally no. Most conventional mortgages allow extra principal payments without a penalty, but read your loan documents or ask your servicer. Make sure extra funds go toward principal, not future payments.

Which is better for a first-time buyer?

Many first-time buyers prefer a 30-year for the lower required payment and the breathing room while they build savings. Then they add extra payments when they can. A higher payment can also make it harder to qualify, so compare both on a loan estimate and consider speaking with a qualified housing counselor or loan officer.