15-Year vs. 30-Year Mortgage: Which Should You Actually Choose?

The 15-year mortgage has better numbers. That part isn't really in dispute: lower rate, dramatically less interest, faster equity. If mortgages were a math problem, the article would end here.

They aren't, and the reason is that the two loans differ in something the interest comparison never captures — what happens to you in a bad year. A 30-year loan you're voluntarily overpaying and a 15-year loan are financially similar and psychologically opposite, because only one of them lets you stop.

This guide covers what each term actually costs, what the interest difference really is, how much faster equity builds, and the specific situations where the worse deal is the better decision.

A note before you start: this is general education, not personalized financial advice. Rates used throughout — 6.65% for 30-year and 5.95% for 15-year — are the Freddie Mac Primary Mortgage Market Survey averages for the week of August 20, 2026. Your rates will differ by lender and credit profile, and the gap between the two terms moves over time. All figures were computed with the same engine behind the calculators on this site.

1. The monthly difference

On a $320,000 loan — a $400,000 home with 20% down:

The 15-year costs $637.42 more every month — about 31% more.

That's the number that decides this for most people, and it's worth being concrete about what it represents. It isn't $637 of luxury spending you could trim. It's $637 that has to appear every month for fifteen years, in months when the water heater fails and months when a bonus doesn't arrive.

Note also that the payment gap is much smaller than the term gap. Halving the term doesn't double the payment — it raises it by under a third — because you stop paying interest so much sooner. That's the whole appeal.

2. Why the shorter loan gets a lower rate

The 15-year rate in these examples is 5.95% against the 30-year's 6.65% — a 0.70-point discount that is not a promotion or a teaser.

Lenders price duration risk. A 30-year loan commits money for three decades, through whatever inflation and rate environments arrive. A 15-year loan returns that capital in half the time, so it carries less of that risk and costs less. The gap varies with market conditions — sometimes it's a quarter point, sometimes more than a full point — but shorter terms are consistently cheaper.

This compounds the interest advantage: you're paying a lower rate and paying it for half as long. Both effects run the same direction, which is why the total-interest difference is so large relative to the monthly difference.

3. The interest difference, in context

Total interest over the life of each loan:

• 30-year: $419,543.56
• 15-year: $164,506.92
• Difference: about $255,000

On a $320,000 loan, the 30-year borrower pays more in interest than the house cost. That figure gets quoted a lot, usually as an argument that 30-year mortgages are a trap.

It deserves two pieces of context.

First, it's spread over thirty years and not adjusted for inflation. A dollar of interest paid in year 28 is a much cheaper dollar than one paid today. A fixed payment also gets easier to carry as incomes rise — that's a genuine, underrated feature of long fixed-rate debt.

Second, the comparison assumes the $637.42 monthly difference vanishes. In reality it goes somewhere. If a 30-year borrower reliably invests it, the comparison becomes an investment-return question rather than an interest question, and the answer depends entirely on returns nobody can promise. If it gets absorbed into general spending — which is the common outcome — then the $255,000 is real.

The honest framing: the 15-year's advantage is guaranteed and the 30-year-plus-investing alternative is not. How much that certainty is worth is a genuine judgment call, not a calculation.

4. Equity builds far faster

This gets less attention than the interest figure and matters more in the first decade.

Remaining balance on the same $320,000 loan:

After five years the 30-year borrower has paid down $19,933 of a $320,000 loan. The 15-year borrower has paid down $76,999 — nearly four times as much, while paying only 31% more per month.

That gap has practical consequences well before payoff:

• PMI clears much sooner if you started below 20% down (see our PMI guide).
• Selling early is safer. A 30-year borrower five years in has thin equity, and a soft market plus selling costs can leave them writing a cheque at closing.
• Refinancing and home equity borrowing both key off your equity position.

The reason for the gap is amortization: early payments on a long loan are overwhelmingly interest. Our payment guide shows the first payment on this loan is 86% interest.

5. The case for the 30-year

Given all of that, the 30-year still has one advantage that outweighs everything above for many buyers: you can always pay it like a 15-year, but you can never pay a 15-year like a 30-year.

That asymmetry is the entire argument, and it's a strong one. A 30-year mortgage with voluntary extra payments gives you most of the 15-year's benefit and keeps the option to stop. A 15-year mortgage gives you the benefit and removes the option.

The numbers on voluntary overpayment are better than most people expect. On the same $320,000 loan at 6.65%:

An extra $500 a month — less than the $637.42 the 15-year demanded — retires the loan in under 18 years and saves $191,829. That's roughly three-quarters of the 15-year's interest advantage, achieved voluntarily, with the ability to skip a month whenever life requires it.

The catch is behavioural and real: most people don't actually make the extra payment. A required payment gets made; an optional one competes with everything else. If you know from experience that you won't send the money, the 15-year's forced discipline is a feature, and its worse flexibility is the price of that feature.

There's a smaller reason too. Because a 30-year qualifies you at a lower payment, it supports a higher purchase price at the same income — see our affordability guide. Whether that's an advantage or a trap depends on whether you use it to buy the right house or the biggest house.

6. When the 15-year clearly wins

• The higher payment is comfortably inside your budget, not at its edge. If a 15-year payment would put your debt-to-income above roughly a third of gross income, you're buying certainty you may not be able to sustain.
• You're within about 15 years of retirement and want the loan gone before your income changes.
• You've demonstrated you won't overpay voluntarily. Honest self-assessment beats an optimistic plan.
• You have a solid emergency fund — six months or more — so a bad month doesn't immediately become a mortgage problem.
• Rates are high, making the interest saving larger in absolute terms and the shorter-term discount more valuable.

7. When the 30-year clearly wins

• Your income is variable — commission, self-employment, seasonal work. A lower required payment is worth a great deal when income isn't flat.
• You have higher-interest debt. Paying off a credit card at 22% beats accelerating a mortgage at 6.65% by a wide margin.
• You're not maxing tax-advantaged retirement accounts. An employer match is an immediate return no mortgage prepayment can match.
• Your emergency fund is thin. Cash reserves protect the house; extra equity does not — you can't eat equity, and a HELOC can be frozen exactly when you'd need it.
• You're early-career with a strong expectation of rising income, where a payment that feels large now will feel small in ten years.
• You may move within five to seven years. Most of the 15-year's interest advantage accrues late; if you sell early you paid a much higher monthly cost for a benefit you never collected.

8. What about 20-year loans?

Frequently overlooked, and genuinely useful. A 20-year term sits between the two: a payment meaningfully below the 15-year's, a rate usually below the 30-year's, and far less total interest than the 30-year.

Not every lender advertises one, but most will quote it on request. If the 15-year payment is slightly out of reach and the 30-year feels too slow, ask for a 20-year quote before assuming the choice is binary. The same logic extends to custom terms — many lenders will write a 25-year or 18-year loan if you ask.

9. A practical way to decide

1. Calculate both payments on your actual loan amount at your actual quoted rates.
2. Take the 15-year payment and add your other monthly debts. If that exceeds about 36% of gross monthly income, treat the 15-year as out of reach regardless of the interest saving.
3. Ask what the difference would otherwise do. Retirement contributions and high-interest debt both outrank mortgage prepayment.
4. Be honest about whether you'd overpay. If yes, the 30-year gives you flexibility for free. If no, the 15-year buys discipline.
5. Check your emergency fund first. Neither term is safe without one.
6. Ask for a 20-year quote before treating this as a two-way choice.

And note that this isn't irreversible in one direction: a 30-year borrower can refinance into a 15-year later if income rises, paying closing costs to do it (see our refinance guide for whether that pays back). Going the other way — refinancing a 15-year into a 30-year because the payment became unmanageable — requires qualifying at a moment when your finances have probably deteriorated.

10. Biweekly payments: the middle path most people miss

There's a third option that sits between the two terms and gets far less attention than it deserves.

Instead of one monthly payment, you pay half your payment every two weeks. Because there are 52 weeks in a year, that produces 26 half-payments — the equivalent of 13 monthly payments instead of 12. The extra one goes entirely to principal.

On the same $320,000 loan at 6.65%:

Nearly $99,000 saved and six years removed, from a change that costs you one extra monthly payment a year — roughly $171 a month if you think of it that way.

Two practical cautions:

Confirm your servicer applies each half immediately. Some hold the first half until the second arrives, then post one monthly payment. If they do that, you get none of the benefit. Ask directly, then verify on a statement.

Don't pay a third party for this. Companies sell "biweekly programs" for setup and monthly fees. You can achieve the identical result for free by dividing your monthly payment by 12 and adding that amount to each payment as principal-only. Our prepayment guide covers the mechanics.

11. You can change your mind later — in one direction

Neither choice is permanent, but the exits are asymmetric, and that asymmetry should inform the decision.

From a 30-year to a 15-year: refinance. You'll pay closing costs of roughly 2%–6% of the loan, and you'll need to qualify at the higher payment. This is the easier direction because you're typically doing it from a position of strength — income has risen, or you've decided to accelerate. Our refinance guide covers whether the break-even works.

From a 15-year to a 30-year: also a refinance, but you'd be doing it precisely because the payment became unmanageable — which usually means income fell, or expenses rose, or something went wrong. That's exactly the moment lenders are least willing to approve you. The exit you're most likely to need is the one hardest to use.

There's also recasting, which is neither. After a large principal payment, some servicers will re-amortize the remaining balance over the remaining term, lowering the monthly payment without a full refinance. Fees are typically a few hundred dollars rather than full closing costs. It's useful for cash-flow relief but doesn't shorten your loan — the opposite of what a 15-year borrower wants.

12. Where this sits among your other priorities

The 15-versus-30 decision is really a question about where surplus cash should go, and mortgage term is not automatically the best answer.

Things that generally outrank committing to a higher mortgage payment:

• An emergency fund of three to six months. A 15-year payment with no reserve is fragile in a specific way: the payment is contractual, and the equity you've built can't be withdrawn to cover it.
• Employer retirement matching. An immediate 50%–100% return beats a guaranteed 6.65% by a wide margin.
• Debt costing more than your mortgage rate. Credit cards, personal loans, and many car loans.
• Tax-advantaged retirement contributions, which have annual limits you can't reclaim later.

And a genuine argument for the 15-year that the interest comparison misses: for borrowers who would otherwise spend the difference, the forced payment is a savings mechanism that actually works. The right comparison isn't "15-year versus investing the difference" — it's "15-year versus what you'd really do with the difference."

Be honest about which of those two you are. The answer determines which loan is better for you regardless of what the arithmetic says in the abstract.

13. A worked decision

Two households, identical $320,000 loans, opposite right answers.

Household A earns $150,000 with stable salaried income, has eight months of expenses saved, no other debt, and captures the full employer retirement match. The 15-year payment of $2,691.71 is roughly 21% of gross monthly income. They plan to stay long-term.

For them the 15-year is straightforward. The payment sits well inside a comfortable ratio, the reserve absorbs a bad year, and the guaranteed $255,000 of interest savings is money they'd otherwise probably not invest with equal discipline.

Household B earns the same $150,000, but half is commission that varied 35% between the last two years. They have two months of expenses saved and a $22,000 car loan.

The same 15-year payment is the same 21% of average gross income — and in a weak commission year it could be 30% or more, on top of the car payment, with two months of runway. For them the 30-year at $2,054.29 is clearly right, with extra payments in strong years. They get most of the benefit and keep the ability to stop.

The instructive part: identical income, identical loan, identical rates — and the ratio alone doesn't separate them. What does is income stability and reserve depth, neither of which appears in the interest comparison.

That's the general lesson. Run the numbers, then ask what happens in a bad year. The 15-year rewards households whose downside is already covered. The 30-year is built for everyone whose isn't yet — and for anyone who'd rather own the choice than the obligation.

Frequently asked questions

Is a 15-year mortgage always better? Financially, over the full term, it costs far less — about $255,000 less interest in our example. But it demands $637.42 more each month and removes the ability to pay less in a hard year. Better on the spreadsheet is not automatically better for your situation.

How much more is a 15-year payment? On a $320,000 loan at these rates, $2,691.71 versus $2,054.29 — 31% more. The increase is less than proportional to the halved term because you pay so much less interest.

Why is the 15-year interest rate lower? Lenders price duration risk. Committing money for 15 years is less risky than 30, so it costs less. The gap here is 0.70 points and varies with market conditions.

Can I just pay extra on a 30-year instead? Yes, and it works well: $500 extra a month saves $191,829 and retires the loan in 215 months. The caveat is behavioural — optional payments frequently don't get made.

Which builds equity faster? The 15-year, substantially. After five years it has retired $76,999 of principal against the 30-year's $19,933.

Does a 15-year affect how much house I can buy? Yes — the higher payment means you qualify for less at the same income. Our affordability calculator shows the difference.

What if I take the 15-year and can't afford it later? That's the core risk. Options are refinancing into a longer term (which requires qualifying at that moment) or selling. This is why the 15-year suits borrowers with a comfortable margin, not those stretching to reach it.

Is a 20-year mortgage a real option? Yes, and it's under-used. Most lenders will quote one on request even if they don't advertise it, along with other custom terms.

What to do next

Run both terms on your actual numbers. Our payment calculator shows the full all-in monthly payment — including property tax and insurance, which don't change with your term but do change what you can carry.

From there:

• Affordability calculator — see what each term qualifies you for.
• Your monthly mortgage payment, explained — why early payments are mostly interest.
• Is refinancing worth it? — the route from a 30-year into a 15-year later.
• What is PMI and how do you remove it? — faster equity clears it sooner.

See our methodology page for how every figure on this site is sourced.

This article is general education about mortgage terms, not financial, legal, or tax advice. Figures were computed with CalculatorByState's own calculation engine using a $320,000 loan and the Freddie Mac PMMS 30-year and 15-year rates for the week of August 20, 2026. Your rates, and the gap between terms, will differ. For a real quote, speak with a licensed mortgage lender.