15 vs 30 Year Mortgage: Side by Side
A 15-year mortgage costs more each month but far less over the life of the loan. This calculator places both terms side by side: monthly gap, total interest and what happens if you take the 30-year and invest the difference. On a $295,000 loan at illustrative rates, the 15-year payment can be 40-50% higher but total interest less than half.
Your loan
Taxes, insurance and extra payments
$0.00
on a $0 loan at 0% loan-to-value
- Principal & interest
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- Property tax
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- Home insurance
- $0.00
- PMI
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- HOA dues
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- Total monthly
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Principal overtakes interest in month 0 (—), then most of every payment is yours.
- Total of payments
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- Paid off
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- PMI cancellable
- month —
Estimates from the figures you entered, not a loan offer. Taxes and insurance vary by property; your lender's escrow figure is the one that counts.
The Monthly Payment Gap
The 15-year term compresses the same principal into half the number of payments, which pushes the monthly obligation significantly higher. On a $295,000 loan at an illustrative 6.25% rate, the 30-year payment is roughly $1,816 while the 15-year payment is roughly $2,526 — a gap of about $710 per month. That gap is the core tradeoff: it buys you faster equity growth and dramatically lower total interest, but it also reduces the cash available for other goals every single month.
Fifteen-year mortgages often carry a slightly lower interest rate than their 30-year counterparts, which narrows the gap a bit. The calculator lets you enter separate rates for each term so you can compare using actual quotes from your lender rather than guessing at the spread.
What If You Invest the Difference Instead
The 30-year camp has a reasonable argument: take the lower required payment, invest the $710 monthly difference in a diversified index fund, and the investment returns may outpace the mortgage interest you would have avoided with the 15-year loan. This is mathematically possible when the long-run return on your investments exceeds the after-tax cost of the mortgage.
The calculator includes an optional investment-return field so you can test this scenario. It shows the projected portfolio value at year 15 — the point where the 15-year loan would be paid off — and lets you compare it to the remaining balance on the 30-year loan. The gap between the two is your net position. This comparison is honest about its limitation: investment returns are not guaranteed, while the mortgage interest cost is contractual. If you need certainty, the 15-year path delivers a guaranteed return equal to your interest rate. If you can tolerate volatility and have the discipline to invest the difference every month, the 30-year path may come out ahead — but only if you actually invest the savings.
Investment projections use the return rate you enter and assume consistent monthly contributions. Actual market returns vary and are not guaranteed.
Year-by-year amortization schedule
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