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15 vs 30 Year Mortgage Calculator

June 30, 2026 • By the Investor Sam Editorial Team • Reviewed by Berly Sam Varghese, Editor
A 15-year mortgage carries a higher monthly payment but a lower rate and dramatically less total interest, while a 30-year keeps payments low and frees up cash flow. This calculator puts the two side by side for the same loan amount, showing each monthly payment and the total interest a 15-year term saves. The right choice depends on whether you value a lower payment now or paying far less over the life of the loan.

Example: Loan amount: 350000 $ · 15-year interest rate: 5.85 % · 30-year interest rate: 6.6 %

15-year monthly payment$2,925
30-year monthly payment$2,235
Interest saved with 15-year$278,172

Worked example

On a $350,000 loan, a 15-year at 5.85% costs about $2,916 a month, while a 30-year at 6.6% costs about $2,236 — roughly $680 more each month for the shorter term. But over the life of the loan, the 15-year pays around $175,000 in interest versus about $455,000 on the 30-year, saving nearly $280,000. The trade is a higher monthly commitment now for enormous long-run savings.

Frequently asked questions

Why is the 15-year rate lower?

Lenders take on less risk over a shorter term, so 15-year mortgages typically carry a rate roughly half to three-quarters of a point below comparable 30-year loans. That lower rate compounds the interest savings on top of the shorter payoff.

Is a 15-year mortgage always better?

Not for everyone. The higher payment can strain a budget and crowd out retirement savings or an emergency fund. Some borrowers prefer a 30-year for flexibility and simply pay extra when they can, capturing much of the benefit without locking in the higher required payment.

Can I get a 30-year and pay it off in 15?

Yes. Taking a 30-year and making extra principal payments gives you flexibility — you can pay it down aggressively in good years and fall back to the lower required payment in tight ones. You will pay a slightly higher rate for that option.

How much income do I need for a 15-year?

Because the payment is higher, lenders apply the same debt-to-income limits to a larger number, so you qualify for a smaller loan or need more income for the same home. Check both scenarios against the 28/36 affordability guideline.

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Sources

Berly Sam Varghese · Editor, Investor Sam

Berly Sam Varghese is an engineer who treats money the way he treats any hard problem — something to be engineered, not gambled on. He funded years of education and built real financial stability the patient way, by living below his means and investing rather than borrowing. He writes for the person trying to make a home a sound decision, not just a purchase. He reviews and approves every article on Investor Sam and checks the figures against primary sources before anything is published. More about our standards.