Free 15 vs 30-year mortgage calculator
Compare 15-year and 30-year mortgages side by side — see monthly payment, total interest, and the break-even of the shorter term, updated live, as you type.
On this page10 sections
Rate difference between 15 and 30-year is typically 0.5–0.75%. Enter the actual rates quoted to you. Excludes taxes, insurance, and PMI.
Results are estimates. Consult a professional.
How the 15 vs 30-year mortgage calculator works
Both the 15-year and 30-year mortgage use the same standard amortization formula. The difference is the number of monthly payments — 180 vs 360 — and the interest rate. Lenders typically offer 15-year loans at rates 0.25–0.5% lower than 30-year loans because they carry less default risk over time.
The higher monthly payment on the 15-year loan accelerates principal paydown. Each month's interest charge is calculated on a smaller remaining balance, so a growing share of every payment reduces principal. Over 15 years this compounds into dramatic interest savings compared with the slower-burning 30-year schedule.
Freddie Mac Primary Mortgage Market Survey — historical rate spreads between 15- and 30-year fixed.Worked example: $400,000 loan at 2024 rates
Borrower takes a $400,000 mortgage. Lender quotes 6.5% for 15 years or 7.0% for 30 years. We calculate both monthly payments and total interest paid.
Monthly payment and total interest — 15yr vs 30yr
Rates used: 15-year at 6.5%, 30-year at 7.0% (Freddie Mac PMMS averages, early 2024). Taxes and insurance are not included.
| Loan Amount | 15yr Payment | 15yr Interest | 30yr Payment | 30yr Interest | Interest Saved |
|---|---|---|---|---|---|
| $200,000 | $1,743 | $113,700 | $1,331 | $279,160 | $165,460 |
| $300,000 | $2,614 | $170,520 | $1,996 | $418,560 | $248,040 |
| $400,000 | $3,485 | $227,300 | $2,661 | $557,960 | $330,660 |
| $500,000 | $4,356 | $284,080 | $3,327 | $697,720 | $413,640 |
Source: Freddie Mac PMMS; CFPB Mortgage Calculator methodology.
Tips for choosing between a 15 and 30-year mortgage
The right term depends on your cash flow, job stability, and other financial goals. Here are five factors to weigh before you decide.
- Stress-test the higher payment — Run your budget with the 15-year payment and a 20% income drop. If it still works, the 15-year is likely safe. If it feels tight, the 30-year gives you breathing room.
- Compare the rate spread — If the 15-year rate is only 0.125% below the 30-year, the math tilts slightly toward 30-year with voluntary extra payments. A 0.5% spread strongly favors the 15-year.
- Consider your investment alternative — Money not spent on the extra payment could be invested. If your expected after-tax return exceeds the mortgage rate, the 30-year + investing strategy may win over 15 years.
- Check prepayment penalties — Most conventional loans have none. With a 30-year loan, making one extra principal payment per year replicates much of the 15-year savings without the obligation.
- Account for tax deductibility — Mortgage interest may be deductible if you itemize. Higher interest on the 30-year loan means a larger potential deduction, which partially offsets the cost difference.
Accuracy and limitations
This calculator uses standard amortization and a fixed rate for the full term. It does not account for property taxes, homeowner's insurance, PMI, HOA fees, or rate changes. Actual lender quotes will vary based on your credit score, down payment, loan type, and local market conditions. The interest savings shown assume you hold the loan to maturity — if you sell or refinance before the term ends, the comparison changes significantly.
Not financial advice — consult a mortgage professional for your specific situation.
Mortgage term comparison terms defined
About this 15 vs 30-year mortgage calculator
This calculator runs entirely in your browser — nothing you enter is sent to any server.
Browse more in our finance calculators, or explore the complete library on the free calculators page.