How to think about the 15 vs. 30 decision
The 30-year's real product is flexibility: a lower required payment that you can voluntarily exceed. The 15-year's product is discipline plus a rate discount: a lower rate you can't get otherwise, and a forced savings plan. Financially, the 15-year wins if you'd otherwise spend (not invest) the payment difference; the 30-year wins if the difference would go to higher-return uses — retirement accounts with an employer match, or paying off expensive debt. The wrong answer is taking the 15-year payment when it crowds out your emergency fund: house-rich, cash-poor is a fragile position.
Frequently asked questions
How much more is the payment on a 15-year vs. a 30-year mortgage?
Typically 40–50% higher, not double — because 15-year rates run about half a point lower and far less of your payment goes to interest. On $300,000, a 30-year at 6.5% is about $1,896/month while a 15-year at 5.9% is about $2,516 — $620 more.
How much interest does a 15-year mortgage save?
Usually more than half of the 30-year’s total interest. In the example above, the 30-year costs about $382,000 in interest versus about $153,000 for the 15-year — roughly $230,000 saved. The exact figure for your loan and rates appears in the table above.
Why are 15-year mortgage rates lower?
Shorter loans are less risky for lenders — less time for rates, inflation, and borrower circumstances to move — so they price 15-year money about 0.5–0.75 points below 30-year money. That discount is a real part of the 15-year advantage, which is why this calculator asks for both rates separately.
Is a 15-year mortgage worth it?
If the higher payment fits comfortably — after retirement savings, emergency fund, and other goals — the 15-year is one of the most efficient wealth builders available: equity accumulates 3–4× faster in the early years. If the payment would strain you, a 30-year with voluntary extra payments gives similar math with an escape hatch: you can stop the extras anytime.
What about a 30-year paid like a 15-year?
Taking the 30-year and paying the 15-year payment amount gets you most of the benefit with full flexibility — but not all of it, because your rate stays at the higher 30-year level. The difference is exactly the rate spread; test it in our extra-payment calculator and compare with the table here.
Can I refinance a 30-year into a 15-year?
Yes, that’s a common move once income grows or the balance shrinks. Run the numbers in our refinance calculator — enter your remaining balance and a 15-year term, and check the break-even month on closing costs.
Does a 15-year loan affect how much house I can afford?
Yes — the higher required payment reduces the maximum price under lender debt-to-income ratios. If you’re choosing between a bigger house on a 30-year and a smaller one on a 15-year, our affordability calculator (set the term to 15) shows the price impact directly.
Related calculators
- Mortgage Calculator — Estimate your full monthly payment — principal, interest, property taxes, insurance, PMI, and HOA — with a complete amortization schedule.
- Extra Payment Mortgage Calculator — What paying more each month (or one lump sum) does to your mortgage payoff date and interest.
- Refinance Calculator — Find your break-even month and lifetime savings before you refinance.
- Home Affordability Calculator — How much house can you afford? Income, debts, and the 28/36 rule turned into a real price range.
Disclaimer: Educational purposes only — not financial advice. See our Terms of Use.