15-Year vs. 30-Year Mortgage: Which Saves You More Money?
A shorter term saves interest; a longer term protects cash flow. Here is the real math behind the trade-off, with a side-by-side payment example.
The Short Version
A 15-year mortgage almost always costs less overall. You pay interest for half as long and usually get a lower rate to start with. A 30-year mortgage costs more across the life of the loan but leaves far more room in your monthly budget.
The right answer depends less on which loan is better on paper and more on what your budget can carry every single month, in a bad year as well as a good one.
- 15-year: lower rate, much less total interest, roughly double the equity growth.
- 30-year: lower required payment, more buying power, more flexibility.
- You can always pay a 30-year loan down faster. You cannot make a 15-year payment smaller.
What the Difference Looks Like in Dollars
Use a $350,000 loan amount as the reference. Shorter terms typically price about half a point to three quarters of a point below 30-year terms, and that gap compounds over the life of the loan.
The 15-year payment is meaningfully higher every month, and that is the whole decision. The interest savings are real, but they only matter if the payment is comfortable.
| 30-year term | Lower monthly payment, interest paid over 360 months |
| 15-year term | Roughly $700-$750 more per month, interest paid over 180 months |
| Total interest difference | Well over $250,000 in favor of the 15-year term |
| Equity after five years | Roughly double on the 15-year term |
Why a 15-Year Term Can Save You More
Three forces work together: a better rate, a shorter runway for interest to accrue, and faster principal reduction from the very first payment.
- Lower interest rate - shorter terms typically price better.
- Less time paying interest - the balance shrinks quickly instead of sitting there.
- Faster equity growth - useful if you plan to sell, refinance, or borrow later.
- Debt-free sooner - many buyers target a payoff before retirement.
A 20-year term splits the difference. So does taking a 30-year loan and adding one extra principal payment a year - that alone can cut roughly four to six years off the loan.
Why a 30-Year Term Might Still Be the Better Call
A lower required payment is not a consolation prize. It is protection. Job changes, medical bills, and repairs do not schedule themselves around your amortization table.
- Lower monthly payment leaves room for retirement savings and an emergency fund.
- More buying power - a lower payment can support a larger loan amount.
- Flexibility - pay extra when you have it, without being locked into it.
- Opportunity cost - money invested elsewhere may outperform the interest saved.
Choosing a 15-year payment you can barely cover is riskier than choosing a 30-year loan and prepaying. Reserves protect the loan; a tight payment strains it.
How to Decide
Run both payments against your actual budget, not your best month. If the 15-year payment leaves you with at least three months of reserves and room to keep saving for retirement, it is usually the cheaper path. If it does not, take the 30-year and prepay when you can.
- Compare both payments including taxes, insurance, and any mortgage insurance.
- Check what each term does to your debt-to-income ratio and your approval amount.
- Ask for both quotes side by side before you lock anything in.