Compare 15-year vs 30-year mortgage payments, total interest, and savings side by side. See how much you save with a shorter term and decide which is right for you.
The choice between a 15-year and 30-year mortgage is a trade-off between monthly flexibility and long-run borrowing cost. A 15-year term usually carries a higher required payment but less total interest, while a 30-year term lowers the required payment but stretches borrowing costs over a much longer horizon. The term also changes how quickly equity builds and how much room you keep in the monthly budget for other goals.
This side-by-side comparison calculator lets you enter one loan amount and compare the two repayment paths at their respective rates. You can see the payment difference, total interest for each term, and the interest savings from choosing the shorter option.
The mathematically cheaper option is often the shorter term, but the practical choice depends on whether the higher payment still leaves enough room for savings, reserves, and other obligations.
Knowing the monthly payment difference is easy, but weighing that against the long-run interest cost is harder. This calculator puts both in the same view so you can decide whether the extra monthly payment for the shorter term is worth the reduction in lifetime borrowing cost.
If the 15-year payment is too tight, a longer term with voluntary extra payments can be a useful comparison case.
M = P × [r(1+r)^n] / [(1+r)^n − 1] Applied twice: 15-year: n₁ = 180 months, r₁ = 15yr rate / 12 / 100 30-year: n₂ = 360 months, r₂ = 30yr rate / 12 / 100 Savings = Total Interest (30yr) − Total Interest (15yr)
Result: 15yr: $2,906/mo | 30yr: $2,212/mo | Save about $273,247
A $350,000 loan at 5.75% over 15 years costs about $2,906/month with roughly $173,158 in total interest. The same loan at 6.5% over 30 years costs about $2,212/month, about $694 less per month, but accrues roughly $446,406 in total interest. Choosing the 15-year term saves about $273,247 in interest but requires the higher monthly payment.
The appeal of a 30-year mortgage is the lower monthly payment, but the longer term usually means far more total interest. The exact difference depends on the rate spread and loan size, which is why a side-by-side worksheet is more useful than a generic slogan about shorter terms always winning.
A 15-year mortgage can build equity much faster because a larger share of each payment goes to principal earlier in the schedule. That can matter if your goal is to own the property free and clear sooner or lower lifetime housing costs.
The strongest argument for a 30-year mortgage is flexibility, not cost. Life is unpredictable, and a lower required payment can leave more room for reserves and optional extra payments when cash flow is strong.
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This page solves the mortgage payment formula twice for the same loan amount: once using a 15-year term and once using a 30-year term. It then compares monthly payment, total interest, total paid, and the amount of principal repaid after five years under each schedule.
It is a term-comparison worksheet rather than a recommendation engine. Real borrowing decisions should still account for closing costs, reserves, other debt obligations, and the actual rate spread quoted by the lender for each term.
Savings depend on the loan amount and the actual rate spread between the two terms. The shorter term usually reduces total interest materially because the balance is repaid faster and often at a lower rate.
Shorter terms often receive lower pricing because the lender exposure ends sooner and the balance amortizes faster. The size of the rate gap changes with market conditions and lender pricing.
A good test is whether the higher payment still leaves enough room for reserves, retirement saving, maintenance, and other recurring obligations. A 30-year with voluntary extra payments can preserve flexibility if the fixed 15-year payment feels too tight.
These middle-ground options offer lower payments than 15-year but less total interest than 30-year. A 20-year mortgage typically has a rate close to the 15-year and saves substantial interest. Not all lenders advertise them, but they are usually available on request.
That depends on your expected after-tax investment return, time horizon, and risk tolerance. Paying less mortgage interest creates a guaranteed saving, while investing the payment difference introduces market risk and behavior risk.
This hybrid approach gives you flexibility: you can make 15-year-level payments when finances are good and revert to the minimum when they are tight. The downside is you do not get the lower 15-year rate, so your effective savings are slightly less.
The shorter term pays principal down faster, so equity from repayment builds more quickly. This calculator’s five-year comparison gives a cleaner way to see that effect than a rule-of-thumb statement.
The mortgage interest deduction reduces the effective cost of interest, which slightly favors the 30-year (more interest = larger deduction). However, with the higher standard deduction, many borrowers no longer itemize, reducing this advantage.