15-Year vs 30-Year Mortgage: Total Cost, Monthly Payment, and Which Wins
On a $300,000 loan, a 15-year mortgage at 6.5% costs about $2,620/month and saves over $150,000 in total interest compared to a 30-year loan at 7.0% ($1,996/month) — but only if your budget can absorb the higher payment.
15-Year Mortgage vs 30-Year Mortgage: Side-by-Side
| 15-Year Mortgage | 30-Year Mortgage | |
|---|---|---|
| Monthly payment ($300k loan) | ~$2,613 at 6.5% | ~$1,996 at 7.0% |
| Total interest paid ($300k) | ~$170,000 | ~$419,000 |
| Total interest savings vs 30-yr | $249,000 saved | Baseline |
| Typical interest rate (2024) | 0.50–0.75% lower than 30-year | Higher than 15-year |
| Equity build speed | Fast — half the loan paid in ~5 years | Slow — mostly interest early |
| Flexibility | Less (larger required payment) | More (can pay extra voluntarily) |
| Best for | Stable income, near retirement, refinancers | First-time buyers, growing families |
Which should you choose?
Pick the 15-year mortgage if you can comfortably afford the higher payment — the interest savings are enormous and you'll build equity much faster. Pick the 30-year mortgage if the difference in monthly payment would strain your budget or cut into emergency savings, investments, or retirement contributions.
The 30-year's lower payment lets you invest the difference, which can also compound significantly.
The interest cost difference is enormous
On a $300,000 home loan, the lifetime interest difference between a 15-year and 30-year mortgage is staggering. The 15-year loan (at 6.5%) pays about $170,000 in interest. The 30-year loan (at 7.0%) pays about $419,000. That's a $249,000 difference — nearly the cost of the original home.
The 15-year loan also typically carries a lower interest rate, usually 0.5–0.75% below the 30-year rate. That rate advantage is baked into the savings above. On a $300,000 loan, a 0.5% rate reduction alone saves over $30,000 in interest over the life of the loan.
Use the mortgage calculator to see the exact breakdown for your loan amount, rate, and term.
Can you beat the 15-year by investing the difference?
The classic counterargument to the 15-year mortgage: take a 30-year loan, invest the $617/month payment difference in the stock market, and you might come out ahead over 30 years.
If you invest $617/month for 30 years at the historical S&P 500 average of 10%, you'd accumulate about $1.4 million — far more than the $249,000 in interest you'd save. This math works in theory.
The non-obvious problem: most people don't consistently invest the difference. The lower payment gets absorbed into lifestyle spending. If you're confident you'll invest it, the 30-year math can favor you. If history shows you spend extra income rather than invest it, the 15-year's forced savings wins.
Refinancing: can you get 15-year benefits with a 30-year loan?
You can mimic a 15-year loan on a 30-year mortgage by making extra principal payments. If you add $617/month in extra principal on a $300,000 / 30-year / 7.0% loan, you pay it off in about 15 years and save almost the same in interest.
This hybrid approach gives you the lower required payment of a 30-year (financial flexibility) while hitting the 15-year payoff timeline if you stay disciplined. Many financial planners recommend this strategy: take the 30-year but pay as if it's a 15-year. In a financial emergency, you can drop to the minimum payment.
The actual 15-year loan is the right choice when you want an external commitment that enforces discipline — you can't easily skip payments — and when you're close to retirement and want a paid-off home.
Which mortgage term is right for your stage of life?
Stage of life matters more than most mortgage comparisons admit. A 35-year-old with a growing family and variable income often benefits from the 30-year's flexibility — career changes, kids, and unexpected expenses are common.
A 50-year-old refinancing a nearly paid-off home or a high earner in their peak years is the ideal 15-year borrower. They have stable income, kids are older, and they want the mortgage gone before retirement.
First-time buyers with limited savings should almost always choose the 30-year. The lower payment preserves cash for an emergency fund and retirement contributions — both of which often yield more than the interest savings of a 15-year mortgage early in your career.
Frequently asked questions
Is a 15-year mortgage always better than a 30-year?
Not always. The 15-year saves more in total interest, but only if the higher payment doesn't crowd out emergency savings or retirement contributions. A 30-year mortgage with disciplined extra payments can achieve similar results with more flexibility.
What is the interest rate difference between 15 and 30-year mortgages?
In 2024, 15-year mortgage rates run about 0.50–0.75% lower than 30-year rates. On a $300,000 loan, that rate difference alone saves about $30,000–$45,000 in interest over the 15-year term.
Can I pay off a 30-year mortgage in 15 years?
Yes — by making extra principal payments. Adding the equivalent of one extra monthly payment per year can shave 4–7 years off a 30-year mortgage. Paying the full "difference" between the 15 and 30-year payments can bring your payoff timeline close to 15 years.
Which mortgage is better for refinancing?
If you're refinancing with 10–15 years left on a 30-year mortgage, switching to a 15-year often makes sense — you may not change your payoff date much, but you'll get a lower rate and build equity faster. Always compare total cost over your remaining time horizon, not just monthly payment.