A 15-year mortgage costs more per month. A 30-year mortgage costs less per month but far more in total interest over the life of the loan. Everything else in this decision flows from that one tradeoff.

Neither term is a trick or a bad deal. Lenders price both fairly, based on the risk they’re taking on. Your job is matching the term to your actual finances and goals. Don’t just pick whichever one sounds more responsible.

Take a $350,000 mortgage. At a 6.5% rate on a 30-year term, the monthly principal and interest payment runs around $2,212. Shorten the term to 15 years, and the rate typically drops too. Lenders often charge half a percentage point to a full point less, since they view shorter loans as less risky. Even with that lower rate, the 15-year payment on the same loan lands around $2,950 to $3,000 a month.

That’s roughly $750 to $800 more every month for the 15-year option. For many households, that gap is the entire decision right there. If $800 a month doesn’t fit your budget without strain, the 15-year term isn’t a realistic option. That’s true no matter how appealing the total interest savings look on paper.

On that same $350,000 loan, the 30-year term at 6.5% racks up roughly $446,000 in total interest over its full life. The 15-year term at 5.75% racks up roughly $170,000 instead. That’s a difference of around $276,000. It’s more than three-quarters of the original loan amount, paid or saved purely based on which term you picked.

This is the number that makes the 15-year term so appealing on paper. But it ignores something. What could you have done with that extra $800 a month if you’d invested it instead of paying down your mortgage faster? The comparison isn’t as one-sided as the interest total alone suggests.

A 30-year mortgage with a lower monthly payment frees up cash. That cash can go toward retirement accounts, an emergency fund, or other investments. Historically, long-run stock market returns have exceeded typical mortgage interest rates by a meaningful margin. Money invested instead of used for early payoff has often grown faster than the interest it would have saved.

This isn’t guaranteed, though. Markets don’t move in a straight line. A guaranteed interest saving from a 15-year term carries none of the risk that comes with investment returns. Our guide on paying off your mortgage early walks through this exact tradeoff in more detail.

A 15-year mortgage builds home equity much faster than a 30-year one. Two things drive that: the loan amortizes quicker, and more of each payment goes toward principal from day one. Our Amortization guide shows exactly how that split shifts over a loan’s life. Faster equity growth means you’d owe less relative to your home’s value if you needed to sell or refinance a few years in.

There’s a flip side, though. That extra cash going into home equity isn’t liquid. You can’t easily tap it for an emergency without selling the home or taking out a new loan against it. A 30-year mortgage, paired with disciplined saving elsewhere, keeps more of your money accessible in cash or investments instead.

Here’s an option many buyers overlook. Take out a 30-year mortgage. Then voluntarily pay it down as if it were a 15-year loan, by making extra principal payments each month. This gets you most of the interest savings of a shorter term, without locking you into the higher required payment.

The advantage is flexibility. In a tight month, drop back to the required 30-year payment, no penalty, no default. In a strong month, pay extra and shrink your payoff timeline. There’s a tradeoff, though: you’ll typically pay a somewhat higher rate than a true 15-year loan offers, since the rate is set by the loan’s stated term, not by how fast you actually pay it down.

Because the required monthly payment is higher, lenders factor that larger payment into your debt-to-income ratio. Our Debt-to-Income Ratio guide covers how this calculation works. Here’s the practical effect: the same income that qualifies you for a $400,000 home on a 30-year term might only qualify you for $310,000 to $330,000 on a 15-year term. More of your income gets consumed by the higher required payment.

Check this early in your search, before you fall in love with a home priced for a 30-year budget. Our how much house can you afford guide covers the underlying affordability math either term relies on.

Some buyers plan to start with a 30-year term and refinance into a 15-year loan later, once income rises or rates improve. This can work, but it isn’t free. Refinancing comes with closing costs, typically 2% to 5% of the loan amount, and it resets your amortization schedule, meaning you go back to paying mostly interest again in the early years of the new loan.

Weigh the refinance closing costs against the interest savings before assuming this path automatically beats committing to one term from the start. Sometimes it does. Sometimes the fees eat into the benefit more than expected, especially if you refinance more than once over the life of the loan.

A 15-year mortgage taken out at 30 finishes around 45, leaving decades of mortgage-free years to save aggressively for retirement or other goals. The same 15-year mortgage taken out at 55 finishes at 70, right around a typical retirement age, which can feel like cutting it close if income drops right as the higher payment is still due.

A 30-year mortgage taken out later in life sometimes still makes more sense purely for cash flow reasons, even though it stretches loan payments further into retirement than most people would ideally want. There’s no universal right answer here. Run the math against your own timeline, not a generic rule of thumb built around a 30-year-old first-time buyer.

Mortgage interest can be deductible for taxpayers who itemize, and a 30-year loan generates more total interest, which means more potential deduction in the early years compared to a 15-year loan at the same balance. In practice, this rarely changes which term makes sense for a given household. Standard deduction thresholds mean many homeowners don’t itemize at all, and even for those who do, the deduction only offsets a fraction of the extra interest cost, not all of it.

Treat this as a minor factor at most. Building your decision around a tax deduction that may or may not apply to your situation is rarely a good foundation for a choice this size.

Say you’re financing $300,000. A 30-year term at 6.5% puts your monthly principal and interest payment around $1,896. A 15-year term at 5.75% puts it around $2,489. That’s a difference of about $593 a month.

Over 30 years, the first loan costs about $382,600 in total interest. Over 15 years, the second loan costs about $148,000. Take that extra $593 a month from the 30-year option and invest it at an average 7% annual return over 15 years. It would grow to somewhere around $185,000 to $190,000. That’s more than the interest the 15-year term would have saved, though the guaranteed interest reduction doesn’t carry the same market risk.

Some lenders offer a lower rate on either term in exchange for paying discount points upfront, essentially prepaid interest. This can make sense if you plan to stay in the home long enough to recoup the upfront cost through lower monthly payments. It rarely makes sense if you might move or refinance within a few years.

Factor these upfront costs into your comparison alongside the interest rate itself. A 15-year loan with points paid upfront might look slightly different in total cost than the same loan without points, and the breakeven point on those points is worth calculating before you agree to pay them.

Our Mortgage Calculator lets you compare both terms side by side using your actual loan amount and rate, rather than rough averages. Want to understand the underlying mechanics of how a mortgage payment splits between principal and interest? Our how mortgages work guide covers the basics both terms are built on.