15 vs. 30 Year Mortgage
Compare a 15-year and a 30-year mortgage on the same loan — the payment difference versus the interest you save.
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How the 15 vs. 30 year mortgage calculator works
Choosing between a 15-year and a 30-year mortgage on the same loan amount is a trade between monthly cash flow and lifetime cost. The 15-year demands a noticeably higher monthly payment because you compress repayment into half the time, but you build equity fast and pay dramatically less total interest.
The 30-year keeps payments low and flexible, yet you carry the debt twice as long and interest accumulates accordingly. Fifteen-year loans also tend to come with slightly lower rates. This calculator runs both side by side so the payment gap and the interest savings are plain.
Worked example: with loan amount of $300,000, 15-year rate of 6.57% and 30-year rate of 7.18%, the 15 vs. 30 year mortgage shows interest saved with the 15-year of $259,151.
- 15-year payment
- $2,624.88
- 15-year total interest
- $172,478
- 30-year payment
- $2,032.30
- 30-year total interest
- $431,630
The formula
Each option uses the standard amortization formula on the identical principal, differing only in term (180 versus 360 months) and rate. Total interest equals the monthly payment times the number of payments, minus the original principal. The 15-year's higher payment is offset by far fewer payments and usually a lower rate.
How every calculator here computes, what it assumes and how the defaults stay current: our methodology.
- The same loan amount is compared; only the term and rate differ between the two options.
- Fifteen-year loans are assumed to carry a slightly lower rate, as they typically do, though you can set rates equal.
- Total interest figures assume the loan runs to term with no extra principal payments on either option.
- Taxes, insurance, and PMI are excluded; they would apply similarly to both terms and do not change the comparison.
- The analysis ignores the opportunity cost of the higher 15-year payment, which some borrowers would invest instead.
15- vs 30-year mortgage at today's rates (6.57% vs 7.18%)
Monthly principal and interest and lifetime interest for common loan sizes at the current Freddie Mac average rates.
| Loan | 15-yr payment | 30-yr payment | Difference / mo | 15-yr interest | 30-yr interest | Interest saved |
|---|---|---|---|---|---|---|
| $250,000 | $2,187.40 | $1,693.59 | +$493.81 | $143,732 | $359,691 | $215,959 |
| $350,000 | $3,062.36 | $2,371.02 | +$691.34 | $201,225 | $503,568 | $302,343 |
| $450,000 | $3,937.32 | $3,048.46 | +$888.86 | $258,718 | $647,444 | $388,727 |
Rates refresh weekly. The 15-year rate runs about 0.61 percentage points lower today, which is part of why the interest gap is so large.
15- or 30-year: which term fits you
Both are fixed-rate loans; the difference is how fast you repay and what that speed costs. On a $350,000 loan at today's averages:
| 15-year | 30-year | |
|---|---|---|
| Monthly payment (P&I) | $3,062 | $2,371 |
| Total interest | $201,225 | $503,568 |
| Equity from payments after 5 years | $81,147 | $19,913 |
| Required payment | Higher and mandatory every month | Lower; extra payments are optional |
| Qualifying | Harder — the bigger payment raises your debt-to-income ratio | Easier — the lower payment leaves more room |
| Usually suits | Higher, steady incomes; buyers within ~15 years of retirement | First-time and budget-conscious buyers; variable incomes |
A simple rule: if you can make the 15-year payment every month — even in a bad one — while still saving for retirement and keeping an emergency fund, the 15-year wins on cost. If not, take the 30-year: a tight budget with no margin is a bigger risk than paying more interest.
Take the 30-year, pay it like a 15
A middle path: borrow on a 30-year term but send the 15-year payment each month. You can drop back to the lower required payment in a tight month; the cost is the 30-year's higher rate (7.18% vs 6.57% today).
| Loan | Payment you send | Paid off in | Interest paid | True 15-year interest | Cost of the flexibility |
|---|---|---|---|---|---|
| $250,000 | $2,187 | 16 yr 2 mo | $172,230 | $143,732 | $28,498 |
| $350,000 | $3,062 | 16 yr 2 mo | $241,121 | $201,225 | $39,897 |
| $450,000 | $3,937 | 16 yr 2 mo | $310,013 | $258,718 | $51,296 |
Extra dollars go straight to principal, so you still erase most of the 30-year interest — just not quite as much as a real 15-year loan, because the rate is higher. If the full 15-year payment feels like a stretch, a 20-year term splits the difference on both payment and interest.
Results are estimates for educational purposes and are not financial advice. Confirm exact figures with your lender or a licensed advisor.
Questions about the 15 vs. 30 year mortgage calculator
Is taking a 30-year loan and paying it like a 15 just as good?
Close, but not identical. You keep the flexibility to drop back to the lower required payment if money gets tight, which is valuable.
However, 30-year loans usually carry a higher rate than 15-year loans, so even with aggressive prepayment you pay slightly more interest. You also need the discipline to actually send the extra each month rather than spending it.
How much interest does the 15-year really save?
Typically a very large share — often more than half the total interest of the 30-year, sometimes far more. Two forces compound: you borrow for half as long, and you usually get a lower rate.
The catch is the monthly payment, which runs substantially higher because the same principal is squeezed into 180 payments instead of 360. Run your own figures to see the exact gap.
Does a 15-year mortgage make it harder to qualify?
It can. The higher monthly payment raises your debt-to-income ratio, so a lender may approve you for a smaller loan on a 15-year term than on a 30-year. Borrowers stretching to afford a home often need the 30-year simply to pass underwriting. If you comfortably clear the income test, the 15-year's savings are compelling.
Is my information saved or shared?
No. Every calculation runs entirely in your browser. We never store, transmit or sell the numbers you enter.
Can I refinance from a 30-year into a 15-year later?
Yes, and many borrowers do once their income grows. Weigh the closing costs and the rate you would get against simply paying extra on the loan you already have — extra principal shortens a 30-year without any refinance costs.
Is a 15- or 30-year mortgage better?
A 15-year carries a higher payment but a lower rate and far less total interest; a 30-year keeps payments low and flexible. Pick 15 if the higher payment fits comfortably, 30 if you value breathing room or want to invest the difference. This tool compares both side by side.
Sources
- Freddie Mac — Primary Mortgage Market Survey (weekly average rates)
- CFPB — Loan Estimate explainer
- CFPB — Fixed-rate vs adjustable-rate mortgages
How the figures on this site are calculated and tested: methodology · editorial policy.
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