Short answer: the 15-year mortgage almost always saves dramatically more in interest — in our example, about $273,000 less on a $350,000 loan — but costs roughly $694 more per month. The 30-year mortgage wins on monthly cash flow and flexibility. Which is “better” depends on whether your budget can absorb the higher payment without strain.
The numbers, side by side
Using illustrative rates — 6.5% on the 30-year and 5.75% on the 15-year (15-year rates typically run lower than 30-year rates) — here’s a $350,000 loan:
| 30-year at 6.5% | 15-year at 5.75% | |
|---|---|---|
| Monthly principal & interest | $2,212 | $2,906 |
| Total interest paid | $446,406 | $173,158 |
| Total paid | $796,406 | $523,158 |
The 15-year loan costs $694 more per month but saves $273,248 in interest — you pay back about 1.5 times the loan instead of 2.3 times. Two forces drive the gap: the shorter term gives interest less time to compound, and the lower rate means less interest accrues each month. Model your own loan amount on our Loan Amortization Calculator to see both schedules.
Why the interest gap is so large
Mortgage interest is front-loaded: in the early years, most of each payment covers interest and only a sliver reduces principal. On the 30-year loan above, the first monthly payment of $2,212 includes about $1,896 in interest and only $316 in principal. The 15-year loan’s $2,906 payment includes about $1,677 in interest and $1,229 in principal — nearly four times as much principal from day one.
That early principal reduction is the whole game. Every dollar of principal eliminated in year 1 stops generating interest for the remaining life of the loan. The 15-year structure forces rapid principal paydown; the 30-year structure lets the balance linger, compounding against you.
Breakeven thinking: the middle path
You don’t have to choose a 15-year loan to get 15-year-like results. Take the 30-year loan at 6.5% but pay it like the 15-year — $2,906 a month instead of $2,212:
- The loan pays off in about 196 months (16.3 years) instead of 360
- You keep the flexibility to drop back to $2,212 in a tight month (job loss, emergency), which a 15-year loan doesn’t allow
The catch is discipline: the 30-year loan doesn’t force the extra payment, so it only works if you actually make it every month. Automating the higher amount as your regular payment removes the temptation to skip.
There’s also the investing counterargument worth taking seriously: if you can reliably earn more than your mortgage rate elsewhere (say, in a retirement account), the 30-year’s lower payment frees cash to invest. The 15-year’s guaranteed “return” is the interest you avoid — roughly the mortgage rate, risk-free. Neither answer is wrong; it’s a question of risk tolerance and discipline.
Who the 15-year mortgage suits
- High, stable earners who can comfortably absorb the larger payment while still saving for retirement
- Borrowers close to retirement who want the mortgage gone before their income drops
- Refinancers who are already years into a 30-year loan and want to finish on the original timeline
- Disciplined-averse borrowers — if you know you won’t voluntarily make extra payments, the 15-year forces the issue
Who the 30-year mortgage suits
- First-time buyers stretching to afford the home at all — the lower payment is what makes ownership possible
- Borrowers who value flexibility — the lower required payment is a safety buffer in uncertain times
- Investors who prefer to direct extra cash into higher-return opportunities rather than home equity
- Anyone in a high-cost area where the 15-year payment would consume an unhealthy share of income
A useful rule of thumb: if the 15-year payment would exceed about 28% of your gross monthly income, the 30-year is probably the safer choice. You can always pay extra; you can’t easily pay less on a 15-year loan.
Frequently asked questions
How much can you save with a 15-year mortgage instead of a 30-year?
It depends on the loan size and the rate gap, but it’s typically enormous. On a $350,000 loan with illustrative rates of 5.75% (15-year) versus 6.5% (30-year), the 15-year saves about $273,000 in interest — at the cost of roughly $694 more per month. Run your numbers on the Loan Amortization Calculator.
Is a 15-year mortgage always better than a 30-year?
No. The 15-year wins on total interest, but the higher payment reduces your monthly flexibility and leaves less cash for investing, emergencies, or other goals. If the payment strains your budget, the 30-year with voluntary extra payments is the safer structure.
Can I get 15-year benefits with a 30-year loan?
Yes — pay the 30-year loan as if it were a 15-year. On a $350,000 loan at 6.5%, paying $2,906 a month (the 15-year payment) instead of $2,212 pays the loan off in about 16.3 years. The key is automating the higher payment so you don’t skip it.
Do 15-year mortgages have lower interest rates?
Typically, yes. Lenders usually offer lower rates on 15-year terms than 30-year terms because the shorter term means less risk for the lender. The exact gap varies with market conditions — check current rates rather than assuming a fixed spread.
Which is better if I might sell in a few years?
If you’ll sell within 5–7 years, the 15-year builds equity much faster, which matters when you sell. But the higher payment also means less cash on hand for your next move. Compare the equity difference against your cash-flow needs before deciding.
Should I refinance from a 30-year to a 15-year mortgage?
It can make sense if current 15-year rates are meaningfully below your existing rate and you can handle the higher payment. Watch the closing costs — divide them by your monthly savings to get the breakeven point in months, and only refinance if you’ll keep the loan past breakeven.
Reviewed September 2026. Examples computed with the standard US mortgage amortization formula; rates shown are illustrative examples, not current market rates. This article is educational content, not financial advice.