A 15-year mortgage has a higher monthly payment but far less total interest, while a 30-year has a lower payment but costs much more over time. On a $300,000 loan at example 2026 rates, the 15-year at about 6.0% runs about $2,532 a month and costs roughly $155,700 in interest. The 30-year at about 6.8% runs about $1,956 a month but costs roughly $404,100 in interest, about $248,000 more. You trade a lower monthly payment for a much larger lifetime cost.
Picture the same $300,000 loan on two different clocks. On the 15-year clock you pay about $2,532 a month and hand the bank roughly $155,700 in interest. On the 30-year clock you pay about $1,956 a month, but you hand the bank roughly $404,100 in interest. Same house, same loan amount, about $248,000 difference.
That single gap is what the whole 15-versus-30 decision comes down to. One choice costs less every month; the other costs far less overall. Neither is a trap. They just serve two different goals, and the right answer depends on your budget and how much flexibility you need.
This is the clearest side-by-side of the two, with the real dollar figures behind each. All numbers use example 2026 rates and standard month-by-month amortization. This is educational math, not refinance or lending advice.
1. The Real Trade-Off in One Sentence
Here is the whole decision in plain terms: a shorter term means a bigger monthly payment but a much smaller pile of interest, and a longer term means a smaller monthly payment but a much bigger pile of interest. That is it. Everything else is detail.
Two things drive the difference. First is the term itself, 15 years versus 30 years of interest piling up. Second is the rate. Lenders usually offer 15-year loans at a lower rate than 30-year loans, often around half a point to a full point lower, because a shorter loan is less risky for them. So the 15-year wins twice: fewer years and a better rate.
The catch is the monthly number. A 15-year payment is roughly a quarter to a third higher than a 30-year payment on the same loan. That higher payment is real money you have to find every single month, in good months and tight ones alike.
Roughly how much more interest a 30-year mortgage costs than a 15-year on a $300,000 loan, using example 2026 rates of about 6.8% and 6.0%.
2. The Full Math on a $300,000 Loan
Let's put real numbers on the same $300,000 loan. The 30-year uses an example 2026 rate of about 6.8%. The 15-year uses about 6.0%, reflecting the lower rate these loans typically carry. These are illustrative figures, not quoted rates, your actual rate depends on your credit, lender, and the day you lock.
| $300,000 Loan | Monthly Payment | Total Interest | Total Paid |
|---|---|---|---|
| 30-year @ ~6.8% | $1,956 | $404,079 | $704,079 |
| 15-year @ ~6.0% | $2,532 | $155,683 | $455,683 |
| Difference | +$576 / mo (30-yr lower) | $248,396 saved | $248,396 saved |
Read the two middle numbers slowly. The 30-year payment is about $576 lower every month, real breathing room in a budget. But over the life of the loan, the 30-year costs about $248,000 more in interest. You are essentially paying $576 a month less now in exchange for roughly a quarter-million dollars more later.
There is also a total-cost angle that surprises people. On the 30-year, you pay back $704,079 total on a $300,000 house, more than double the price of the home in interest and principal combined. On the 15-year, you pay back $455,683. The house did not get more expensive; the financing did.
3. See Your Own Numbers
The table above uses a $300,000 loan and example rates. Your loan amount and your quoted rates will be different, and the gap between the two payments is the only thing that decides which loan fits your budget.
You will need three things: your loan amount, your quoted rate for each term, and the number of years. Put them into the free mortgage payoff calculator and it shows the monthly payment, the total interest, and how fast you build equity under each option side by side.
Then try the "what if" that matters most: keep the 30-year loan but add extra to the payment, and watch the payoff date and interest drop. That single experiment often settles the whole decision. Run your real numbers on the calculator here.
4. Who Should Choose the 15-Year?
The 15-year makes the most sense when the higher payment is comfortable, not a stretch. If you can cover about $2,532 a month on this example loan and still fund an emergency fund, retirement, and normal life, the 15-year hands you enormous interest savings and a paid-off house in half the time.
It fits people who value being debt-free by a certain age, retiring without a mortgage, for instance, and who won't feel squeezed by the bigger payment. It also fits savers who would otherwise let the "extra" money drift into spending; the higher required payment forces the saving for you.
Want to shrink your mortgage without switching loans?
The Loan Extra Payment Mini Guide shows you exactly how much to add each month to hit the payoff date you want, in plain English, in about ten minutes.
5. Who Should Choose the 30-Year?
The 30-year makes the most sense when the lower required payment protects you. If about $2,532 a month would leave you with no cushion, the 30-year's roughly $1,956 payment keeps your budget flexible and lowers the risk of ever missing a payment.
It fits people with variable income, growing families, or other high-interest debt to clear first. And it fits anyone who wants the option to invest the difference. If you can reliably earn more on that extra $576 a month than your mortgage rate, the 30-year plus investing can come out ahead, though that depends entirely on discipline and returns, which are never guaranteed.
The honest risk with a 30-year is that the "extra" money never actually gets saved or invested. If it quietly turns into lifestyle spending, you get the higher lifetime interest cost without the benefit that was supposed to justify it.
6. The Middle Path: Extra Payments on a 30-Year
Here is the option most people overlook. You can take the 30-year loan for its lower required payment, then voluntarily pay extra each month to mimic a 15-year, while keeping the freedom to drop back to the smaller payment in a tight month.
Add roughly the $576 difference to a 30-year payment and you shorten the term dramatically and cut a large chunk of the interest. You don't quite match a true 15-year, because the 30-year usually carries a higher rate, but you get most of the benefit plus a safety valve the 15-year never gives you.
That flexibility is the whole appeal. A 15-year locks you into the bigger payment by contract. A 30-year with extra payments lets you choose the bigger payment most months and fall back to the required one when life happens. For many households, that combination of speed and safety is the sweet spot. Use the loan extra payment calculator to see exactly what a given extra amount does to your payoff date.
7. Common Mistakes to Avoid
Judging only by the monthly payment. The 30-year "feels" cheaper because the monthly number is smaller, but the lifetime cost is far higher. Always look at total interest alongside the monthly payment, not just one of them.
Taking the 15-year when the budget is tight. A higher required payment you can barely cover is fragile. If one bad month could make you miss it, the safer 30-year, with extra payments when you can, usually protects you better.
Assuming you'll invest the difference, then not doing it. The 30-year only "wins" if that extra $576 actually goes to work. If it disappears into spending, you kept the higher interest cost and lost the upside.
Forgetting that extra payments are always allowed. You don't have to pick a 15-year loan to pay a loan off in 15 years. On almost any 30-year mortgage you can add to the principal any month you like and shorten the term yourself.
FAQ: 15-Year vs 30-Year Mortgage
Is a 15-year or 30-year mortgage better?
Neither is better for everyone. A 15-year mortgage has a higher monthly payment but far less total interest, while a 30-year has a lower payment but costs much more over time. On a $300,000 loan at example 2026 rates, the 15-year at about 6.0% costs roughly $155,700 in interest and the 30-year at about 6.8% costs roughly $404,100, about $248,000 more. The 15-year is better if you can comfortably afford the higher payment; the 30-year is better if you want a lower required payment and more flexibility. See both side by side on the free mortgage payoff calculator.
How much more is a 15-year mortgage payment than a 30-year?
On a $300,000 loan at example 2026 rates, the 15-year payment at about 6.0% is roughly $2,532 a month and the 30-year payment at about 6.8% is roughly $1,956 a month. That is about $576 more each month for the 15-year, around 29 percent higher. The higher payment is the trade-off for finishing the loan in half the time and paying far less interest.
How much interest do you save with a 15-year mortgage?
On a $300,000 loan at example 2026 rates, a 15-year mortgage at about 6.0% costs roughly $155,700 in total interest, versus roughly $404,100 for a 30-year at about 6.8%. That is about $248,000 saved. The savings come from both the shorter term and the lower rate that 15-year loans usually carry. You can check the exact figure for your own loan with the mortgage payoff calculator.
Why do 15-year mortgages have lower interest rates?
Lenders take on less risk over a shorter term, so they typically offer 15-year loans at a lower rate than 30-year loans, often around half a percentage point to a full point lower. The examples here use about 6.0% for the 15-year and about 6.8% for the 30-year, which reflects that typical gap. A lower rate means more of each payment goes to principal from day one.
Can I just pay extra on a 30-year mortgage instead of taking a 15-year?
Yes. Paying extra on a 30-year loan shortens the term and cuts interest, and it gives you flexibility a 15-year does not: in a tight month you can drop back to the lower required payment. The one downside is that a 30-year usually carries a higher rate, so you will pay a bit more interest than a true 15-year even if you match the payment. For many people the flexibility is worth that small difference. The loan extra payment calculator shows exactly what a given extra amount does.
Does a 15-year mortgage build equity faster?
Yes. Because the term is shorter and the rate is usually lower, a larger share of every 15-year payment goes to principal from the start, so you own more of your home sooner. The trade-off is that this equity is locked into a higher required payment each month, which leaves less room in your budget for other goals like investing or an emergency fund.
