Tool · Money
Type in a home's price, your down payment and the yearly tax and insurance on it, and the calculator shows the full monthly bill — the loan, the tax, the insurance, mortgage insurance if you're putting down less than a fifth, and any dues — on a thirty-year loan and a fifteen-year loan side by side.
Where does each number come from?
- Home price
- The asking price, or the price you’re weighing. The listing.
- Down payment
- Dollars or a share of the price — the calculator converts either way. Below 20% down, a conventional loan needs private mortgage insurance, and the box for it opens up.
- Interest rate, for each term
- Two boxes, because a fifteen-year loan and a thirty-year loan carry different rates. Both start at Freddie Mac’s weekly averages; a lender’s quote has your real ones, and a quote is free.
- Property tax, per year
- On the listing under “tax history”, or on the county assessor’s website for that address. It’s the one number here that’s about the house rather than about you.
- Homeowners insurance, per year
- A quote from an insurer, for that house. There’s no national figure recent enough to stand in for it, so the box starts empty and the bill shows what’s missing until you fill it.
- Private mortgage insurance, per month
- From the lender’s quote; it depends on your down payment and your credit score. The lender is the only source, so the box starts empty too.
- HOA dues, per month
- On the listing, if the home has them.
What moves the answer?
Let’s say the home is $350,000, you’re putting down 10%, and the tax is $4,000 a year with $1,800 of insurance. The loan is $315,000. On a thirty-year loan at 7%, the loan payment is about $2,100 a month; add the tax and insurance and the bill is about $2,600, before mortgage insurance. On a fifteen-year loan at 6.3%, the loan payment is about $2,700 and the bill about $3,200.
Over the life of each loan the interest is where they separate: about $436,000 on the thirty-year, about $171,000 on the fifteen-year. That’s about $265,000 less interest for about $600 more a month. The two columns sit side by side because they’re two different loans with two different prices, and the payment you can carry each month and the interest you’d rather not pay pull in opposite directions.
What does the calculator take as given?
- The rates
- Start at 6.95% for thirty years and 6.26% for fifteen, Freddie Mac’s weekly averages for the week of 17 September 2026. They move every Thursday. Freddie Mac’s survey covers conventional loans within the conforming limit, collected from the applications lenders submit through its system.
- Mortgage insurance
- Fannie Mae’s Selling Guide requires it on a conventional loan above 80% of the home’s value — that is, with less than 20% down. Under federal law you can ask to cancel it once the balance is scheduled to reach 80% of the original value, and the servicer has to end it at 78%. The calculator counts it until then and shows the month it stops.
- FHA loans work differently
- An FHA loan takes 3.5% down at a 580 credit score, charges 1.75% of the loan up front and 0.5% to 0.55% a year on most loans, and on a small down payment the yearly charge lasts the whole loan. The calculator has an FHA switch that uses those figures from HUD’s handbook instead of the private-insurance box.
- What's left out
- Points and closing costs. Adjustable rates. Escrow cushions — servicers collect a little more than the tax and insurance bills so the account never runs short. And the fact that tax and insurance change every year while the loan payment on a fixed loan doesn’t, so the bill in year ten won’t match the bill in year one.
The three-hundred-fifty-thousand-dollar house with ten percent down is one made-up purchase; the listing carries the price, the tax and the dues, an insurer's quote carries the insurance, and a lender's quote carries the rate and the mortgage-insurance figure.
Sources
- Freddie Mac, Primary Mortgage Market Survey — week of 17 September 2026: 30-year fixed 6.95%; 15-year fixed 6.26%; methodology statement on the survey’s scope.
- Fannie Mae, Single Family Selling Guide, B7-1-01, Provision of Mortgage Insurance (published 2 September 2026) — primary mortgage insurance required on a conventional first mortgage with an LTV above 80%.
- Consumer Financial Protection Bureau, “When can I remove private mortgage insurance (PMI) from my loan?”, last reviewed 28 August 2026 — cancellation at 80% of original value on request; automatic termination at 78%.
- U.S. Department of Housing and Urban Development, Handbook 4000.1, edition of 12 August 2026 — II.A.2.a.iv (3.5% minimum required investment), II.A.2.b.i (500–579 score limited to 90% LTV), Appendix 1.0 (upfront premium 1.75%; annual premium 50–55 basis points on loans over 15 years up to $726,200).