Calculate your 15-year mortgage payment and compare it to a 30-year loan. See exactly how much interest you save, how much faster you build equity, and whether a 15-year makes financial sense for you.
Based on $300,000 loan amount — 15yr @ 6.5% vs 30yr @ 7.0%
Enter your loan amount and interest rate to see your monthly payment, total interest cost, and side-by-side comparison with a 30-year mortgage.
Open Mortgage Calculator →The 15-year mortgage is a significantly better financial deal in purely mathematical terms — it always costs less in total interest, always builds equity faster, and comes with a lower interest rate. But the higher monthly payment is a real constraint for many borrowers. The choice comes down to whether you can comfortably afford the larger payment without straining your monthly budget or sacrificing other financial priorities.
At current 2024 rates: a 15-year fixed mortgage at 6.5% has a monthly principal and interest payment of $2,613. Over 180 payments, you pay $470,340 total — including $170,340 in interest. A 30-year fixed mortgage at 7.0% has a monthly payment of $1,996. Over 360 payments, you pay $718,706 total — including $418,706 in interest. The 15-year saves $248,366 in total interest — nearly the full original loan amount. You pay $617 more per month but save a quarter million dollars over the life of the loan.
The 15-year's larger payment demands predictable income. It's ideal for dual-income households with stable employment, professionals with long career trajectories, and government or tenured employees. The $617/month higher payment on a $300K loan requires roughly $25,000–$30,000 in additional annual income to comfortably qualify and afford.
If you're 45–55 and buying or refinancing, a 15-year mortgage means being mortgage-free by 60–70 — before or during your peak retirement years. Entering retirement without a mortgage payment dramatically reduces the income you need from your portfolio. Many pre-retirees specifically use 15-year mortgages or aggressive extra payments to achieve this.
If you're already maximizing your 401k and Roth IRA contributions, and your emergency fund is complete, the 15-year mortgage becomes a compelling form of forced savings — every payment rapidly builds home equity at a guaranteed 6.5% return (your mortgage rate). This is especially attractive in low-return environments.
The 30-year mortgage offers lower required monthly payments — providing crucial financial flexibility. If the difference between the 15 and 30-year payment ($617/month in our example) would be invested consistently in stock market index funds averaging 10% annually, the investment portfolio could outperform the interest savings from the 15-year. This "invest the difference" argument makes the 30-year compelling for disciplined investors with long time horizons. The 30-year also makes more sense for variable-income earners, those with remaining high-interest debt to pay, and anyone in the early years of their career building financial stability.
Many borrowers choose a 30-year mortgage but pay it like a 15-year — making extra principal payments each month while retaining the ability to revert to the lower required minimum in a financial emergency. This provides the security of a lower required payment with the interest savings of accelerated payoff. Adding $617/month extra principal to a 30-year 7% mortgage on $300K results in payoff in about 16–17 years and saves over $200,000 in interest — nearly matching the 15-year outcome without the payment commitment.
On a $300,000 loan: 15yr at 6.5% = $170,344 total interest. 30yr at 7.0% = $419,306 total interest. Savings: approximately $249,000. The 15-year also builds equity roughly twice as fast, giving you a stronger financial position much sooner.
Best for: stable high-income households, pre-retirees wanting to be mortgage-free by retirement, and those who've already maxed out retirement accounts. Less suitable for: variable income earners, early-career buyers, or those who might need payment flexibility in tight months.
On a $300K loan: 15yr at 6.5% = $2,613/mo vs 30yr at 7.0% = $1,996/mo. Difference: $617/month. The 15-year costs 31% more monthly but saves ~$249K in total interest. Whether it's worth it depends on whether you could invest the $617 difference at a better return elsewhere.
Yes — adding $617/month extra principal to a $300K 30-year at 7% pays it off in ~16–17 years, saving $200K+ in interest. This hybrid approach gives 30-year payment flexibility (revert to minimum in emergencies) with near-15-year results. Most mortgages allow extra principal payments without prepayment penalties.