The Real Numbers at 2026 Rates
Let's use a concrete example: a $400,000 home with 20% down (loan amount: $320,000). We'll use current approximate rates — 6.75% for a 30-year and 6.10% for a 15-year (15-year rates are typically 0.5–0.75% lower).
| 30-Year Fixed | 15-Year Fixed | |
|---|---|---|
| Loan Amount | $320,000 | $320,000 |
| Interest Rate | 6.75% | 6.10% |
| Monthly Payment (P&I) | $2,076 | $2,718 |
| Total Interest Paid | $427,360 | $169,240 |
| Total Cost | $747,360 | $489,240 |
| Interest Savings | $258,120 saved with 15-year | |
Monthly Payment vs Total Cost
The fundamental tension with any mortgage term decision is cash flow today vs cost over time. A 30-year mortgage gives you a lower monthly payment, freeing up cash for investments, emergencies, or other goals. A 15-year mortgage costs significantly less over time but puts more pressure on your monthly budget.
The monthly payment difference in our example is $642/month. Over a year, that's $7,704. Over the full 15 extra years of the 30-year loan, that's $138,600 in additional payments — but you'd pay $258,120 more in interest on the 30-year. The math still strongly favors the 15-year if you can comfortably afford the higher payment.
When a 30-Year Mortgage Makes More Sense
- Tight monthly budget: If the 15-year payment would stretch you to the limit, the 30-year gives you breathing room for emergencies, job loss, or unexpected costs.
- You plan to invest the difference: If you take the $642/month savings and invest it consistently in index funds returning 8–10% annually, you could potentially outperform the interest savings — though this requires discipline.
- You'll move within 7–10 years: If you don't plan to stay long-term, the interest savings of a 15-year are less impactful since you'll pay off neither loan in full.
- You're self-employed or have variable income: Lower required payments give you flexibility in lean months.
When a 15-Year Mortgage Makes More Sense
- Stable, high income: If the higher payment is 20–25% or less of your take-home pay, the interest savings are hard to beat.
- You want to retire debt-free sooner: Paying off your home by 50 instead of 65 has enormous lifestyle value beyond the dollar savings.
- You're not a disciplined investor: The 15-year forces savings through equity building, which is more reliable than promising to invest the payment difference.
- Close to retirement: Eliminating a mortgage payment before retiring dramatically reduces how much income you need.
The Middle Ground: Extra Payments on a 30-Year
Many financial advisors recommend a hybrid approach: take the 30-year for its flexibility, but make extra principal payments when you can afford to.
For example, adding just $300/month in extra principal payments to a 30-year mortgage at 6.75% on a $320,000 loan would:
- Pay it off about 8 years early (in ~22 years)
- Save roughly $130,000 in interest
- Give you the option to stop the extra payments if finances get tight
This flexibility is impossible with the 15-year — once you commit to that payment, it's obligatory.
Our Verdict
Choose the 15-year if the monthly payment is comfortably within your budget (ideally under 25% of take-home pay), you value being mortgage-free sooner, and you plan to stay in the home long-term.
Choose the 30-year if budget flexibility matters more to you, you're a disciplined investor, or your income is variable. Consider making extra payments whenever possible.
There's no universally "right" answer — it depends entirely on your income, expenses, risk tolerance, and goals. Run the numbers with your own figures using the calculator above.