True Cost of Homeownership
Most "afford a home" calculators stop at PITI (principal, interest, taxes and insurance). This one adds a CapEx reserve, a monthly amount set aside for the things that will wear out: roof, HVAC, water heater, appliances. The result is closer to what owning the home costs each month.
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How this calculator works ↓New to a term? Money terms explained.
Loan & carrying costs
CapEx reserve: the things that will wear out
Each system has a typical lifespan. The calculator divides its replacement cost by that lifespan to estimate a monthly amount to set aside.
True monthly cost
12-year replacement calendar
Approximate years until each system needs replacement, based on current age you set in the CapEx panel.
| System | Years left | Cost |
|---|
How this calculator works
The mortgage payment is the bill people plan for. The calculator adds the bills that come with it and the ones that arrive years later, then shows one all-in monthly figure. It is built from five pieces:
- Principal and interest. Purchase price minus down payment is the loan. The monthly payment uses the standard fixed-rate mortgage formula at your interest rate and term, the same one a lender uses.
- Property tax and insurance. You enter each as a yearly bill and the calculator divides by 12. Together with principal and interest they make up PITI. Most lenders collect them monthly through escrow, an account the lender pays the bills from.
- PMI. If the loan is more than 80% of the price (a down payment under 20%), the calculator adds PMI, private mortgage insurance, at 0.55% of the loan amount per year. At 20% down or more it is zero.
- HOA and routine upkeep. HOA (homeowners association) dues and the monthly upkeep you enter, such as lawn care or pest control, are added as they are.
- CapEx reserve. For each of seven systems (roof, HVAC, water heater, appliances, windows, siding, driveway) the calculator divides the replacement cost by the lifespan in years, then by 12. The sum is the CapEx reserve: what you would set aside each month so the money is there when a system wears out. No bill arrives for it until the day one does, which is why most payment calculators leave it out.
All-in monthly is the sum of all five. With the example numbers the loan payment is about $2,506 and the all-in figure is about $3,517, so roughly $1,011 a month sits outside the loan payment.
The replacement calendar uses the age you enter for each system. Lifespan minus current age gives the years left, and the table lists every system due within 12 years, soonest first. The reserve itself does not change with age: it spreads the full cost over the full lifespan. If you buy a home with a 20-year-old roof, the calendar shows the bill coming sooner than the reserve alone would cover.
Two simplifications to know about: PMI is shown as of the day you buy and is not removed as the loan is paid down, and every cost is held at today's prices.
Assumptions and where they come from
| Assumption | Default | Source / note |
|---|---|---|
| Default price and down payment | $425,000 and $42,500 (10%) | An example close to the U.S. median sales price of houses sold, $410,700 in the second quarter of 2026 (Census Bureau and HUD, via FRED). The 10% down payment keeps PMI visible in the example. |
| Default interest rate and term | 6.85%, 30 years | A placeholder. Freddie Mac's weekly survey put the average 30-year fixed rate at 7.28% on October 1, 2026 (Primary Mortgage Market Survey). Rates move every week; enter the rate you are quoted. |
| Default property tax | $4,675 per year (1.1% of the price) | A placeholder. Effective property tax rates vary widely by county, from under 0.5% of a home's value to about 2% (Tax Foundation, 2026). Use the bill on the listing or the county assessor's site. |
| Default insurance | $1,488 per year | In the range of the national average homeowners premium: $1,569 in 2022, the latest year the National Association of Insurance Commissioners has published (Insurance Information Institute). That figure is several years old and premiums differ a lot by state; use a quote for the home. |
| PMI | 0.55% of the loan per year when the down payment is under 20% | A placeholder. Real PMI pricing depends on your credit score, down payment and loan type; the lender's Loan Estimate shows the actual amount. The Consumer Financial Protection Bureau explains what PMI is and when it can be removed. |
| System lifespans | Roof 25 years, HVAC 15, water heater 10, appliances 12, windows 25, siding 30, driveway 20 | Round figures in or near the ranges on InterNACHI's life expectancy chart, for example 20 to 30 years for asphalt shingle roofs, 6 to 12 for conventional water heaters and 15 to 20 for asphalt driveways (InterNACHI). Siding and windows vary the most by material. Climate and upkeep move all of them. |
| Replacement costs | Roof $12,000, HVAC $8,000, water heater $1,800, appliances $5,000, windows $9,000, siding $14,000, driveway $4,500 | Placeholders for a mid-sized house, not taken from a survey. Costs depend heavily on region, house size and materials. Replace them with local quotes where you can. |
| Maintenance benchmark | Reserve plus upkeep come to about 0.9% of the price per year | Fannie Mae describes a rule of thumb of 1% to 4% of a home's value per year for maintenance, repairs and replacements (Fannie Mae). The defaults sit near the low end; an older home may warrant higher costs or shorter lifespans. |
| Inflation | None | Taxes, insurance and replacement costs are held at today's prices. In practice all three tend to rise over time. |
| Not modelled | Closing costs, utilities, income-tax effects, home appreciation, and the return the down payment could have earned elsewhere (opportunity cost) | Add utilities to other monthly upkeep if you want them in the total. |
Assumptions last reviewed: October 2026.
Frequently asked questions
What is the true monthly cost of owning a home?
It is the mortgage payment plus everything else the home makes you pay: property tax, homeowners insurance, PMI if your down payment is under 20%, HOA dues, routine upkeep and a reserve for big replacements. With this calculator's example numbers (a $425,000 home, 10% down, 6.85% for 30 years) the loan payment is about $2,506 a month and the all-in cost is about $3,517, so the loan is roughly 71% of the total.
How much does home maintenance cost per year?
A common rule of thumb, used by Fannie Mae among others, is 1% to 4% of the home's value per year for maintenance, repairs and replacements, with newer homes near the low end and older homes near the high end. This calculator builds the figure from the bottom up instead: seven major systems, each with a replacement cost and a lifespan, plus the routine upkeep you enter. The example numbers come to about 0.9% of the home's price per year.
What is a CapEx reserve?
CapEx is short for capital expenditures: the large, infrequent replacements such as a roof, a furnace or a water heater. A CapEx reserve is money set aside every month so the cash is there when one of them fails. The calculator divides each system's replacement cost by its lifespan in years, then by 12, to get a monthly amount.
When does PMI go away?
PMI (private mortgage insurance) is charged on most conventional loans with less than 20% down. According to the Consumer Financial Protection Bureau, you can ask the servicer to cancel it once the balance is scheduled to reach 80% of the home's original value, and it must end automatically at 78% if your payments are current. This calculator shows PMI as of the day you buy and does not remove it later, so the all-in figure describes the early years of the loan.
Does this include closing costs or the total cost of buying a house?
No. The calculator covers the ongoing monthly cost of owning, not the one-time costs of buying: closing costs, inspections, moving and furnishing are left out. It also leaves out utilities unless you add them to the other monthly upkeep field.
Does it work for my state?
Yes, as long as you enter your own property tax and insurance. Those two costs differ the most by location, so the calculator asks for the actual yearly bills instead of guessing from a state average. The listing or the county assessor shows the tax bill, and an insurance quote gives the premium.
This calculator is educational. It is not financial, tax, investment or legal advice. The assumptions are simplified; check them against your own situation or a licensed professional before acting on a result. See the Terms of Use.