Every estimate should show its work.

The short version

• We start from take-home pay, not gross income. Federal tax, payroll tax, and your state’s income tax come out before anything else is computed.
• “Comfortable” means two things at once. Housing stays under about 28% of take-home pay, and after the house and your other debts there’s still enough left for a normal household budget. Both have to be true.
• Costs come from where you’re buying. Your county’s real property-tax rate, insurance scaled to local risk, and your state’s actual transfer taxes and title costs — not one national average.
• The price moves everything. Property tax, home insurance, and mortgage insurance all scale with the price as you drag the slider, and we solve the whole equation exactly in both directions — pick a price and see the cost, or pick a monthly amount and see the price.
• We show the lender’s number next to ours. The same engine also computes what standard qualifying math could approve, so the gap between “approved” and “comfortable” is visible instead of hidden.
• Every number below shows its source. What’s real data, what’s modeled from real data, and what’s still a labeled placeholder.

How we calculate it

Principal and interest

Standard fixed-rate annuity formula, with inverse solving for payment-budget mode.

House Poorness Index

Take-home income minus true housing cost, debts, and a baseline for everyday non-housing spending that scales with your income and household size — the breathing room left each month.

True housing cost

Loan payment (principal and interest), property tax, home insurance, mortgage insurance, HOA or condo fees, maintenance, and utilities.

Upkeep, utilities & HOA

Maintenance uses the standard rule of thumb — 1% of the home's value per year, divided across twelve months. It's a planning estimate, not a quote; older homes typically run higher. Utilities are a flat monthly estimate — the last remaining placeholder value in this calculator. HOA or condo fees are simply whatever you enter. None of the three are required by a lender to qualify you for a loan — a lender's math skips maintenance and utilities entirely — and that gap between what a lender counts and what a home actually costs to live in is the reason this calculator exists.

Closing costs

Ranges for lender fees, title and settlement, transfer taxes, recording, and prepaid taxes and insurance.

Where the data comes from

Property tax rate

US Census American Community Survey — median real estate taxes paid divided by median home value, measured at the county level. We fetch this for every county in the United States in one build-time pull, so any ZIP resolves to a real county rate. ZIP-to-county mapping uses the Census 2020 ZCTA-to-county relationship file; when a ZIP straddles more than one county we use the county covering the largest share of its area and say so. Some counties are top-coded by the Census (taxes capped at $10,000 or more, home value at $2,000,000 or more); where that happens we flag the rate as approximate instead of implying false precision.

Home insurance

NAIC Homeowners Insurance Report 2022 state average premium for the standard HO-3 owner-occupied policy, published through the Insurance Information Institute, for all 50 states and DC. We take the real state average as the midpoint and model a low-to-high range around it — so the base number is real and the spread is modeled. Every county then gets a local risk multiplier built from the FEMA National Risk Index: we add up the expected annual building loss from the perils a standard policy actually covers — hurricane and straight-line wind, hail, tornado, wildfire, and winter storms — as a share of the county's building value, then normalize within each state so the state's average premium is redistributed across its counties, not inflated. Flood and earthquake are deliberately left out of this multiplier, because a standard policy excludes them; we surface them as risk flags instead. Because a pricier home costs more to insure — but not proportionally more — we scale the premium with home price in two parts: half of the local average premium is treated as fixed (liability coverage, base policy costs, and the like, which don't grow with the house), and half scales per dollar of price, calibrated against the state's median home value (US Census ACS). A home priced at the state median pays exactly the risk-adjusted state average, so the anchor is real data; the 50/50 split is our stated modeling judgment. Why not a straight per-dollar rate? Insurance covers the cost to rebuild, not the land underneath, and published premium-by-coverage tables show premiums climb notably slower than home value — a straight rate would quote a cheap home almost nothing (deceptively low) and overcharge an expensive one. The two-part model keeps a sensible floor under modest homes and flattens the top end. One more deliberate choice: the calculator budgets the HIGH end (75th percentile) of the modeled range, not the midpoint. Insurance is the line item most likely to surprise a buyer — it varies address by address more than anything else we model — and a comfort-first plan should be surprised down, not up. The full range is always shown next to the number. If you have an actual quote, type it into “Fine-tune local costs” and we’ll use your fixed dollar figure instead of the modeled estimate.

Risk flags

Up to three plain-language flags per county come from the FEMA National Risk Index county hazard ratings, shown when a hazard rates Relatively High or Very High. Covered perils (hurricane and wind, hail, tornado, wildfire, winter storms) are phrased as premium pressure, since they are already baked into the insurance multiplier. Flood and earthquake are called out separately with a warning that a standard homeowners policy does not cover them — flood needs its own policy and depends on the address's flood zone, and earthquake coverage is a separate add-on. Flags are sorted so the most severe risks show first.

Mortgage rates

Freddie Mac Primary Mortgage Market Survey weekly averages for the 30-year and 15-year fixed loan, fetched live from the Federal Reserve (FRED) and cached for about a day.

State income tax

State income tax comes from the Tax Foundation's “State Individual Income Tax Rates and Brackets, 2026” table (rates as of February 11, 2026). For all 50 states and DC we model an effective rate — tax owed divided by gross income — at a range of incomes for both single and married-filing-jointly filers, applying each state's own tax brackets, standard deduction, and personal exemption, so the estimate rises with income and shifts with filing status. The nine no-income-tax states show zero; Washington's capital-gains tax is left out because it does not apply to wages. Honest caveats: this is modeled from the published brackets and does not account for tax credits (or their phase-outs), local income taxes (such as New York City, Maryland counties, and Ohio cities), or the way retirement contributions and other deductions interact with state rules. Treat it as a close estimate, not a filed return.

Closing costs

We research the tax a home sale triggers when the deed changes hands — sometimes called a transfer tax, conveyance tax, deed tax, or recordation tax depending on the state — for every state, plus the cities and counties that charge their own on top: New York City, Philadelphia, Chicago, San Francisco, Baltimore, Washington D.C., and more. Many states charge one flat rate; some (Washington, Connecticut, Hawaii, Vermont, New Jersey, New York, D.C.) step the rate up as the price climbs. Who customarily pays — the buyer, the seller, or a 50/50 split — varies by state and is baked into each entry, so the number in your closing-cost total only ever counts the buyer's customary share; the rest shows up as a note so it's never quietly dropped or quietly billed to the wrong side. Title insurance (the policy that protects against a defect in the property's ownership history) follows the same two-track approach as other estimates here: Texas, Florida, and New Mexico set their premiums by law, so we run their exact published rate tables; every other state leaves rates to competition, so we use a nationwide curve built from published cost studies that declines as a share of price the more expensive the home is. Transfer-tax research: researched 2026-07. Title-insurance research: researched 2026-07.

Everyday spending baseline

The residual side of the comfort test — how much a household typically spends on everything other than the house — comes from the BLS Consumer Expenditure Survey 2024 (the most recent published tables). We start from average annual expenditures by income quintile, then subtract the three things the calculator already counts on their own so we don't double-count: shelter, utilities, and personal insurance and pensions (mostly retirement and Social Security, which come out when we compute take-home pay). What's left — food, transportation, healthcare, household operations and furnishings, apparel, childcare, everything else — is the everyday baseline. We interpolate it along the income curve so a higher income assumes a higher normal standard of living, and adjust for household size using the survey's size-of-household table, normalized to a two-person household. Honest caveats: these are national averages within broad income quintiles, so they don't capture how much cheaper or costlier your specific metro is, and the quintiles blend households of different sizes. It's a good population-level yardstick for "is there room to breathe," not a budget built from your actual spending. Research vintage: researched 2026-07 (BLS CE 2024, published December 2025).

Still a placeholder

Utilities are the last value not yet sourced — a flat monthly estimate that doesn't yet vary by home size or region. It's a reasonable stand-in, labeled as a placeholder, until real data is wired in. (State income tax and the everyday-spending baseline are no longer placeholders — see above.)