15-Year vs 30-Year Mortgage: Payment, Interest and Trade-offs
The term of a mortgage is one of the biggest choices you make after the price and the rate. A 30-year term spreads the debt thinly, which gives a lower payment and more breathing room. A 15-year term roughly doubles the speed of repayment, which costs much less interest overall but asks for a bigger payment every month.
This guide compares the two with the same loan amount, shows how large each effect is, and covers the factors that numbers alone do not capture. The interest rates used are illustrative, not current quotes.
A side-by-side example
Example: a loan of 300,000. Shorter terms often carry a lower rate, so assume 6.0% for the 15-year loan and 6.5% for the 30-year loan. The payments come from the standard loan formula.
| Measure | 15-year at 6.0% | 30-year at 6.5% |
|---|---|---|
| Monthly payment (P&I) | 2,531.57 | 1,896.20 |
| Total repaid | 455,683 | 682,633 |
| Total interest | 155,683 | 382,633 |
| Balance after 5 years | 228,027 | 280,833 |
The 15-year payment is 635.37 a month higher, about 33% more. In return, the interest bill is about 227,000 lower, and after five years the balance is about 52,800 smaller. The shorter loan builds ownership of the home much faster.
How much comes from the term, and how much from the rate
The example mixes two effects: a shorter term and a lower rate. To separate them, run the 15-year loan at the same 6.5% as the 30-year one. The payment becomes 2,613.32 and the total interest 170,398. So even with no rate discount, the shorter term cuts interest from 382,633 to about 170,400, and the lower 6.0% rate takes it down further to 155,683.
In other words, most of the saving comes from the shorter term itself. The rate discount is a bonus. This also means that if a lender offers no rate advantage for the shorter term, the interest saving is still large, though the payment is higher still.
A middle path: a 30-year loan with extra payments
A 30-year loan can be paid off early by sending more than the required payment. If you pay 2,531.57 a month on the 30-year 6.5% loan, which is the 15-year payment, the loan is cleared in 191 months, about 15 years and 11 months. The total interest is about 181,250, which is more than the 155,683 of the true 15-year loan because of the higher rate, but far below 382,633.
The difference is flexibility. With the longer loan, the required payment stays at 1,896.20, so if your income drops or an emergency arises, you can fall back to the lower figure. With the 15-year loan, the higher payment is a commitment for the whole term. The price of that flexibility is the rate gap and the discipline of paying extra on purpose. See the article on paying off a loan faster for how extra payments work.
A simple way to decide
- Work out the payment for each term using the quotes you have actually been given, and add estimated tax and insurance to both.
- Compare each total with your monthly budget after your other commitments, not just against your gross income.
- Decide how much cash you want to keep in reserve after the down payment and closing costs, then check that either payment still leaves that cushion intact.
- Compare the total interest and the balance after the number of years you realistically expect to hold the loan.
- If the shorter payment is a stretch, consider the longer term together with a standing plan to pay extra when you can.
What the numbers do not capture
- Cash flow. A higher required payment leaves less room for other goals, such as savings, children, or a change of job.
- Qualification. Lenders look at your income against your monthly debts, so a bigger payment can limit how much you are allowed to borrow.
- Opportunity cost. Money not spent on the higher payment could be saved or invested, with an uncertain result. A guaranteed saving at your loan rate should be weighed against returns that are not guaranteed.
- Time horizon. If you expect to move or refinance within a few years, you may never see the long-run interest difference, though the faster equity build helps either way.
- Other debts. Higher-rate debts, such as credit cards, are usually worth clearing before committing to a larger mortgage payment.
Run your own figures in the loan calculator, trying different terms and rates, and look at the payment, the total interest and the balance after the number of years you expect to stay.
This article is general education and not financial advice. The rates above are made up for illustration and your own offers will differ. Consider the full picture or speak to a qualified adviser before choosing a term.
- Loan Calculator: Enter the amount you want to borrow, the term, the interest rate and how often you will pay. You get the size of each payment, the total you will repay and the interest you will pay.
This article is general information, not professional advice. See our Disclaimer and Editorial Policy.
More articles
APR vs APY: What the Two Rates Really Tell You
APR and APY are two ways to quote the same rate. One ignores compounding and one includes it, and mixing them up can make a worse deal look better.
APR vs Interest Rate: What the Difference Means for a Loan
A loan with the lower interest rate is not always the cheaper loan. The APR folds in certain fees so offers can be compared, and a worked example shows how.
How to Calculate a Pay Raise and What It Is Worth After Inflation
A 3.5% raise on $52,000 is $1,820, but what does it buy? Learn the raise formulas, the effect of back-to-back raises, and how inflation changes the picture.