Is a 15-year or 30-year mortgage better?

Short answer: the 15-year mortgage saves you an enormous amount of interest and builds equity fast, but it comes with a much higher required monthly payment that reduces your flexibility. The 30-year costs far more in total interest but gives you the option to pay extra when you can. For most households, the 30-year with disciplined extra payments is the more resilient choice — though the 15-year wins on pure math.

This is usually framed as a math problem, and the math is not close: on the same loan amount, a 15-year mortgage at a lower rate can save you hundreds of thousands of dollars in interest compared to a 30-year. But a mortgage is not just a math problem. It is a 15- or 30-year commitment that has to survive job changes, recessions, medical bills, and all the other things life does. The right answer balances the spreadsheet against your actual life.

The interest savings are real and enormous

Let us be concrete about what is at stake. On a $400,000 loan, the difference between a 15-year and a 30-year mortgage — with the 15-year typically carrying a rate roughly half to three-quarters of a point lower — can easily exceed $200,000 in total interest paid over the life of the loans. That is not a rounding error; it is a second house worth of money, or a retirement fund.

Two mechanisms create the savings. First, the interest rate on 15-year loans is almost always lower than on 30-year loans, because the lender's money is at risk for half as long. Second, you pay that rate for half as many years, and the amortization schedule means you start attacking principal much earlier. In the early years of a 30-year mortgage, the brutal truth is that most of your payment goes to interest; on a 15-year, you build equity from the start.

If your goal is to minimize the total cost of the house and you can comfortably afford the payment, the 15-year is the clear winner. Nobody disputes this part.

The payment difference is the real decision

The catch is the monthly payment. A 15-year mortgage payment is typically 40 to 50 percent higher than the 30-year payment on the same loan amount — not double, because the lower rate and shorter term partially offset, but dramatically higher all the same. On that $400,000 loan, the difference can be on the order of $800 to $1,000 more every single month, required, non-negotiable, for fifteen years.

That required payment is the heart of the tradeoff. A 30-year mortgage gives you a lower floor: in a bad month, a bad year, a job loss, you owe the smaller amount. You can always pay more than the minimum — and if you consistently pay the 15-year amount on a 30-year loan, you will pay it off in roughly the same time, at a slightly higher total cost (because of the rate difference). But you cannot pay less than the minimum on a 15-year loan. Flexibility only flows one way.

This is why so many financial planners describe the 30-year as "a 15-year with an escape hatch." You get most of the interest savings if you are disciplined, and you keep the lower required payment for the months when discipline is not the problem — cash flow is.

What the higher payment costs you elsewhere

The 15-year's bigger payment does not just reduce flexibility; it has an opportunity cost. That extra $800–$1,000 a month could otherwise go to retirement accounts, a child's education fund, or simply a cash reserve. Over fifteen years, money invested in a diversified portfolio has historically grown substantially — and while past performance is no promise, the expected return on long-term investing has typically exceeded mortgage rates, which means every extra dollar sent to the mortgage is a dollar not compounding elsewhere.

This is the strongest argument against the 15-year for younger buyers in particular: the same dollars that would shave years off a mortgage could be doing decades of compounding in a retirement account. The mortgage interest you save is a guaranteed return — valuable and real — but it is often a lower return than what the money could earn invested, and it is entirely illiquid until you sell or refinance.

None of this means the 15-year is wrong. It means the comparison is not "interest saved versus nothing" — it is "interest saved versus everything else the money could do." One more factor in that comparison: in the US, mortgage interest on a primary residence is generally tax-deductible for those who itemize, which slightly reduces the effective cost of borrowing — and reduces it more for the 30-year, since you pay more interest. In practice this matters less than it used to, since far fewer households itemize under the larger standard deduction; if you do not itemize, the deduction is worth nothing to you. Do not let the tax tail wag the mortgage dog.

Qualification and buying power

There is a practical wrinkle many buyers discover late: the higher 15-year payment affects how much house you can qualify for. Lenders evaluate your debt-to-income ratio using the actual required payment, so choosing a 15-year loan reduces the purchase price you can be approved for — sometimes substantially. If you are stretching to buy in an expensive market, the 30-year may be the difference between buying the house you need and not buying at all.

The 15-year also leaves less room in the monthly budget for the true cost of homeownership beyond the mortgage: property taxes, insurance, maintenance (budget roughly 1 percent of the home's value per year), and the inevitable surprises. A payment that looks comfortable on paper can feel very different after the furnace dies in February.

Who the 15-year is actually right for

The 15-year shines for specific profiles. Buyers who are older and want the house paid off by retirement — a 45-year-old who wants no mortgage at 60, for example. Households with high, stable incomes and large cash reserves, for whom the higher payment does not constrain anything else. People refinancing who are already several years into a 30-year and want to finish on schedule without resetting the clock. And anyone who knows themselves well enough to admit they will not actually make those voluntary extra payments on a 30-year — for them, the forced discipline of the 15-year is a feature, not a bug.

Be honest in this self-assessment. The "I'll get a 30-year and pay it like a 15-year" plan is excellent on paper and fails in practice for a large share of the people who attempt it, because voluntary extra payments compete with every other demand on the budget. If you choose the 30-year with this intention, automate the extra payment from day one — make it as non-optional as the 15-year payment would have been.

The third option: splitting the difference

You are not limited to the two standard choices. Many lenders offer 20-year mortgages, which capture a good share of the 15-year's interest savings with a meaningfully lower payment. And as noted, a 30-year paid aggressively functions as a customizable term: pay the 15-year amount and you finish in about 15 years; pay the 20-year amount and you finish in about 20. You can even recast — some lenders let you make a large lump-sum payment and re-amortize the loan at the lower balance, reducing the monthly payment for a small fee.

The existence of these middle paths is another argument for starting with the 30-year: it preserves every option, while the 15-year commits you upfront.

Refinancing can change the answer later

The term you choose at purchase is not permanent. If you start with a 30-year and rates fall meaningfully a few years later, refinancing into a 15-year (or a 20-year) lets you capture the lower rate and shorter term at a moment of your choosing — often with a payment similar to your original 30-year payment, because rates dropped. Conversely, if you start with a 15-year and life gets tighter than expected, refinancing into a 30-year can cut the required payment, though you will pay closing costs for the privilege and reset the interest clock.

The practical implication: when the choice feels close, lean toward the option that is easier to change later. Moving from a 30-year to a shorter term via refinancing or extra payments is straightforward. Moving from a 15-year to breathing room requires refinancing under potentially worse conditions — and lenders are least enthusiastic about helping precisely when you need it most, such as after a job loss. Optionality has value; price it in.

How to decide

Run both payments against your actual budget — not your current rent, but your full projected housing cost including taxes, insurance, and maintenance. If the 15-year payment still leaves comfortable room for saving, emergencies, and life, and you value being debt-free sooner over maximizing liquidity, take the 15-year and enjoy the enormous interest savings. If the 15-year payment would make the budget tight, or you are early in your career with growing income ahead, or you simply sleep better with a lower required floor — take the 30-year, automate extra payments toward your real target, and revisit annually.

Either way, the biggest lever is not actually the term you choose — it is the price of the house. A cheaper house on a 30-year beats an expensive house on a 15-year in almost every scenario that matters. Get the purchase price right, and the mortgage term becomes an optimization. Get it wrong, and no term length will save you.