15 vs 30 Year Mortgage Calculator
Choosing between a 15-year and 30-year mortgage is one of the biggest financial decisions you'll make. This calculator compares monthly payments and total interest to show the true cost of each option.
The Real Cost Difference Between 15 and 30 Years
The monthly payment gap between 15-year and 30-year mortgages looks big, but the lifetime interest gap is enormous. On a $350,000 loan, a 30-year mortgage at 6.5% costs $2,212 monthly and racks up $444,320 in interest. A 15-year loan at 5.75% costs $2,908 monthly and just $136,440 in interest.
That's a $307,880 difference in interest—more than the original loan amount. The 15-year borrower pays $696 more per month but owns the home free and clear in half the time with a mountain of savings.
The math gets even better when you consider opportunity cost. Once the 15-year borrower pays off the loan, they redirect that $2,908 monthly payment into retirement accounts for the next 15 years. At an 8% return, that's over $1 million. Meanwhile, the 30-year borrower is still making payments.
Why Most People Still Choose 30 Years
Affordability dominates the decision. A buyer who can afford a $2,200 monthly payment qualifies for a $350,000 loan at 30 years. That same buyer can only borrow $265,000 at 15 years with the same payment, forcing them to buy a cheaper home or come up with a bigger down payment.
Flexibility matters too. A 30-year loan gives you the option to make extra principal payments and pay it off early, but you're not locked into the higher payment if income drops or expenses spike. A 15-year loan offers no such escape hatch—miss payments and you face foreclosure.
Tax considerations play a smaller role post-2017 tax reform, since the standard deduction now exceeds itemized deductions for most households. But high earners in expensive markets still benefit from mortgage interest deductions, and a 30-year loan maximizes deductible interest in the early years.
The Hybrid Strategy: 30-Year Loan with Aggressive Payoff
Some borrowers take a 30-year mortgage and treat it like a 15-year by making extra principal payments. This preserves flexibility—if you lose your job or face an emergency, you can revert to the minimum payment without defaulting.
The downside: a higher interest rate. A 30-year loan at 6.5% versus a 15-year at 5.75% costs an extra 0.75 percentage points. On a $350,000 loan, that's about $175 more in monthly interest, or $31,500 over 15 years if you actually pay it off early. You're paying for flexibility you might never use.
This strategy works best for borrowers with variable income—commission-based salespeople, business owners, freelancers—who need the cushion of a lower required payment but can afford to pay extra when cash flow is strong. For W-2 employees with stable paychecks, the 15-year mortgage's lower rate and forced discipline usually wins.
Frequently Asked Questions
How much higher is a 15-year payment than a 30-year payment?
Typically 50% to 60% higher. On a $350,000 loan, a 30-year payment might be $2,200 while a 15-year payment is around $2,900. The exact difference depends on rates.
How much interest do I save with a 15-year mortgage?
Hundreds of thousands. A $350,000 loan at 6.5% for 30 years costs $444,000 in interest. The same loan at 5.75% for 15 years costs $136,000—a savings of $308,000.
Why is the 15-year rate lower than the 30-year rate?
Lenders assume less risk with shorter loans. You'll pay off the loan faster, reducing their exposure to default, interest rate changes, and inflation. That lower risk earns you a rate discount.
Can I afford a 15-year mortgage?
If the payment fits comfortably within 28% of your gross monthly income and leaves room for savings, emergencies, and retirement, yes. If it stretches your budget to the limit, stick with 30 years.
Should I get a 30-year loan and pay it like a 15-year?
This gives flexibility—make extra payments when you can, but you're not locked into the higher payment. However, you'll pay a higher rate and need discipline to avoid spending the difference.