Mortgage Comparison Calculator (15 vs 30 Year)
Put two loans next to each other, 15 vs 30 year, two rate quotes, or with and without extra payments, and see exactly what each costs.
Updated October 2026
Data verified for 2026. Educational estimates only, not financial or tax advice.
| Option A | Option B | B − A | |
|---|---|---|---|
| Loan amount | $320,000 | $320,000 | |
| Monthly payment (P&I + extra) | $2,189.48 | $2,805.17 | $615.69 |
| Total interest | $468,213 | $184,930 | -$283,283 |
| Total paid (loan + interest) | $788,213 | $504,930 | -$283,283 |
| Paid off in | 30 yrs | 15 yrs | |
| Interest paid in first 7 yrs | $156,836 | $124,421 | -$32,415 |
| Equity after 7 yrs | $107,081 | $191,213 | $84,132 |
| Balance after 7 yrs | $292,919 | $208,787 | -$84,132 |
15-year vs 30-year mortgage: the real trade-off
A 15-year loan carries a lower rate (usually 0.5–0.75 points less) and pays far less total interest, often less than half. The price is a much higher monthly payment, roughly 40–50% more on the same loan. The 30-year gives you flexibility: a lower required payment, with the option to pay extra when you can. This calculator shows both the lifetime numbers and the picture at the year you actually expect to sell or refinance, because most people don't keep a mortgage for 30 years.
The preset button loads this week's average 30-year and 15-year rates from Freddie Mac so the comparison reflects the real market.
Comparing two rate quotes
Set both options to the same term and down payment and change only the rate. A quarter-point difference on a $320,000 30-year loan is about $50 a month and $18,000 over the life of the loan. If one lender charges points to get the lower rate, add the cost of points to your down payment in that option and compare the equity line at the year you plan to leave; that shows whether buying the rate down pays off before you sell.
30-year with extra payments vs 15-year
A popular middle path: take the 30-year and pay it like a 15-year. Set Option A to 30 years with an extra payment equal to the difference, and Option B to 15 years. You'll see the 15-year still wins on interest (its rate is lower), but the 30-year keeps the option to drop back to the minimum in a hard month. Many people value that insurance more than the interest saved.
Don't forget the opportunity cost
The callout under the table estimates what the monthly difference could grow to if invested at 7% instead of going into the house. For long horizons that number often exceeds the interest saved by the shorter loan, which is why investors with cheap mortgages often prefer the 30-year. For a guaranteed return and simplicity, the 15-year is hard to beat. Both are reasonable; the calculator just makes the trade explicit.
Frequently asked questions
Is a 15-year mortgage always cheaper?+
In total interest, yes, because the rate is lower and the term shorter. In monthly cash flow, no: the payment is 40–50% higher. Compare the equity and interest at the year you expect to sell, not just the lifetime totals.
Can I compare different home prices?+
This tool holds the price constant so the loans compare fairly. To compare two homes, run the mortgage calculator for each and compare the total monthly payments including taxes and insurance.
Should I refinance from a 30-year to a 15-year?+
Set Option A to your current loan balance, rate, and remaining term (enter the balance as price with 0% down), and Option B to the new 15-year terms. If the interest saved by your planned sale year exceeds the closing costs, refinancing likely pays.
Does this include taxes and insurance?+
No. Those are the same for both options, so they are left out to keep the comparison clean. The full mortgage calculator includes them.