The choice between a 15 and 30-year mortgage is really a choice about what to do with roughly $700 a month for fifteen years. Send it to the bank as a bigger payment, and you erase around a quarter-million dollars of interest. Keep it, and you buy flexibility, liquidity, and investment opportunity — at a steep interest cost. Neither answer is universally right, but the numbers make the trade-off unusually concrete.
Here's the full comparison on a $350,000 loan at typical 2026 rates — about 6.3% for a 30-year fixed and 5.6% for a 15-year fixed (the 15-year consistently prices 0.5–0.8 points lower).
The Side-by-Side Numbers
| 30-year @ 6.3% | 15-year @ 5.6% | |
|---|---|---|
| Monthly payment (P&I) | $2,166 | $2,879 |
| Total of payments | ~$780,000 | ~$518,000 |
| Total interest | ~$430,000 | ~$168,000 |
| Principal paid after 5 years | ~$23,000 | ~$90,000 |
| Loan-free date | 2056 | 2041 |
The row most people underestimate is the third one: early equity. In the first years of a 30-year loan, roughly three-quarters of each payment is interest. The 15-year flips that almost immediately — which matters enormously if you might sell within 5–8 years, because equity is what you walk away with.
The Case for the 30-Year (It's Stronger Than It Looks)
- Flexibility is worth real money. The $713/month difference is optional on a 30-year (you can prepay) and mandatory on a 15-year. In a layoff, medical event, or income dip, the lower required payment is the difference between riding it out and forced selling.
- The opportunity cost argument: $713/month invested at a 7% average return grows to roughly $226,000 over 15 years — in the same ballpark as the interest saved, and it's liquid the whole way. At higher expected returns the investing route wins outright; at bond-like returns the 15-year wins. Your mortgage rate is effectively the "guaranteed return" of prepayment: at 6.3%, prepaying is a strong risk-free return.
- Qualification headroom: lenders qualify you on the required payment. The 15-year's higher payment can shrink your approvable price range or push your debt-to-income ratio past limits.
- Higher-priority dollars may exist: maxing an employer 401(k) match (an instant 50–100% return), paying off credit cards (20%+ interest), and funding an emergency fund all beat prepaying a 6.3% mortgage.
The Case for the 15-Year
- The rate discount is free money. The 0.5–0.8 point spread exists only if you commit to the term — a disciplined 30-year prepayer still pays the higher 30-year rate.
- Guaranteed, not hypothetical. The $260k saving requires no market cooperation, no discipline after closing, and no behavioral follow-through. It's structural.
- Retirement alignment: for buyers and refinancers in their 40s–50s, a 15-year term means entering retirement mortgage-free — the single biggest expense line deleted exactly when income drops.
- Forced saving works. The honest version of the opportunity-cost argument admits most people don't invest the difference every month for 180 straight months. The 15-year removes the choice.
The Hybrid: 30-Year Term, 15-Year Behavior
Take the 30-year, then schedule automatic extra principal payments sized to a 15-year payoff. On our example loan, paying $2,879 against the 30-year at 6.3% retires it in about 15.7 years with roughly $186,000 of interest — capturing about 93% of the 15-year's savings while keeping the escape hatch of dropping back to $2,166 whenever life demands it.
Decision Framework
Choose the 15-year if…
- The payment is under ~25% of take-home pay
- Emergency fund (6 months) already exists
- Retirement savings are on track independently
- You're refinancing in your 40s–50s
- You know yourself: unspent money gets spent
Choose the 30-year if…
- Income is variable (commission, self-employed)
- You'd be skipping the 401(k) match to afford the 15-year payment
- High-interest debt still exists
- You're early-career with rising income ahead
- You genuinely will invest the difference — automatically
Run your own numbers — payment, total interest, and debt-to-income — in our free mortgage calculator, and see the payment reduction guide and refinance timing guide for the related decisions.
Frequently Asked Questions
Figures are illustrative calculations at representative 2026 benchmark rates (Freddie Mac Primary Mortgage Market Survey); your rate and numbers will differ. This is general education, not financial advice — consult a licensed professional for decisions about your mortgage.
