15-Year vs 30-Year Mortgage: Complete Cost Comparison
Choosing between a 15-year and 30-year mortgage affects your monthly budget, total interest cost, and how fast you build equity. This guide uses real numbers to show exactly what each option costs.
Quick Comparison
| Factor | 15-Year Mortgage | 30-Year Mortgage |
|---|---|---|
| Monthly Payment ($300K loan) | ~$2,490 at 5.75% | ~$1,896 at 6.5% |
| Total Interest Paid | ~$133,000 | ~$382,600 |
| Typical Interest Rate | 0.5-0.75% lower than 30-year | Higher rate (benchmark rate) |
| Payment Flexibility | Low — higher required payment | High — lower minimum, extra payments optional |
| Equity Building Speed | Fast — own home outright in 15 years | Slow — mostly interest in early years |
| Qualification | Harder — higher DTI requirement | Easier — lower monthly obligation |
The Numbers: $300,000 Loan Comparison
Let us look at a $300,000 mortgage with 20% down on a $375,000 home. As of early 2026, a typical 15-year fixed rate is around 5.75%, while a 30-year fixed rate is around 6.5%. The 15-year rate is lower because the lender's risk exposure is shorter.
With the 15-year mortgage at 5.75%, your monthly principal and interest payment is approximately $2,490. Over the life of the loan, you pay a total of $448,200, meaning $148,200 goes to interest. With the 30-year mortgage at 6.5%, your monthly payment drops to approximately $1,896 — about $594 less per month. However, you pay a total of $682,600 over the life of the loan, with $382,600 going to interest.
The difference is staggering: the 30-year mortgage costs approximately $234,400 more in interest than the 15-year. That is nearly the price of the original loan paid again in interest alone. Even accounting for the time value of money and inflation, the 15-year mortgage saves over $150,000 in today's dollars.
When a 15-Year Mortgage Makes Sense
- You can comfortably afford the higher payment. Financial advisors suggest your total housing cost (mortgage, taxes, insurance) should not exceed 28% of gross income. For a $2,490 payment plus $470 in taxes and insurance, you would need roughly $127,000 in household income.
- You are within 15-20 years of retirement. Entering retirement mortgage-free dramatically reduces your required income and provides financial security.
- You have already built an emergency fund. With the higher payment, you need solid reserves (6 months of expenses) so a job loss does not put your home at risk.
- You want to minimize total cost. If paying the least interest possible is your priority and cash flow allows, the 15-year wins decisively.
When a 30-Year Mortgage Makes Sense
- You need the lower payment to qualify. The $594 monthly difference in our example could be the difference between qualifying for the home you want and being priced out.
- You want to invest the difference. If you take the 30-year mortgage and invest the $594 monthly savings in an index fund averaging 8% returns, after 15 years that investment grows to roughly $205,000. This can outpace the mortgage interest cost if you are disciplined.
- You prioritize cash flow flexibility. Life is unpredictable. The lower required payment gives you breathing room for job changes, medical expenses, or opportunities.
- You have other high-priority financial goals. Maxing out retirement accounts, paying off high-interest debt, or building a business may offer better returns than the interest saved on a 15-year mortgage.
The Hybrid Strategy: 30-Year Term with Extra Payments
A popular middle ground is taking a 30-year mortgage but making extra principal payments as if it were a 15-year loan. This gives you the safety net of the lower required payment while accelerating payoff when cash flow allows. On our $300,000 example, adding $594 per month to the 30-year payment would pay off the loan in about 15.5 years. You would pay roughly $168,000 in interest — about $20,000 more than the straight 15-year mortgage (due to the higher rate) but $214,600 less than making minimum 30-year payments.
The key risk is discipline. If you take the 30-year mortgage intending to make extra payments but spend the difference instead, you end up paying the full $382,600 in interest. Be honest with yourself about whether you will actually make those extra payments consistently.