Methodology & data sources

Data sources

• Property tax rates by state — effective tax rate (median property taxes paid ÷ median home value) from the Tax Foundation's Property Taxes by State and County, 2026, published March 16, 2026. It is built on the U.S. Census Bureau's American Community Survey (2024 5-year estimates). Used by the state selector in the mortgage and rent vs buy calculators.
• Homeowners insurance by state — average annual HO-3 premium from the National Association of Insurance Commissioners (NAIC) Homeowners Insurance Report: Data for 2023 (Table 4), published July 2026. The countrywide HO-3 average in that report is $1,737. Used by the state selector in the mortgage calculator.
• Mortgage rates — rate fields are pre-filled as a starting point, not a quote. Our national benchmark is Freddie Mac's weekly Primary Mortgage Market Survey (PMMS), the most widely cited average for 30- and 15-year fixed loans. Always use the rate from your own Loan Estimate when you have one.
• Lending rules and fees — debt-to-income guidance from the Fannie Mae Selling Guide (B3-6-02) and the CFPB; FHA mortgage insurance from HUD; VA funding fees from the U.S. Department of Veterans Affairs; closing-cost categories from the CFPB.

Important caveat on insurance: NAIC figures are actual premiums written, but they lag about three years. Premiums have risen in many states since 2023, so treat the pre-filled value as a floor and replace it with a real quote when you can.

Mortgage calculator

Formula

Monthly principal and interest uses the standard fixed-rate amortization formula:

M = P × r(1 + r)ⁿ ÷ [(1 + r)ⁿ − 1]

where P is the loan amount (home price minus down payment), r is the annual rate ÷ 12, and n is the term in years × 12. At a 0% rate the payment is simply P ÷ n. The full monthly payment adds:

• Property tax = home price × tax rate ÷ 12. Choosing a state fills in that state's effective rate from the Tax Foundation table.
• Homeowners insurance = annual premium ÷ 12. Choosing a state fills in the NAIC average HO-3 premium.
• PMI = loan amount × PMI rate ÷ 12, applied only when the down payment is under 20% (see the CFPB on PMI).
• HOA dues and extra principal, where the calculator offers those fields, are taken exactly as you enter them. Extra principal is applied to a month-by-month amortization schedule to show the shorter payoff and interest saved.

Assumptions

Fixed rate for the whole term; payments made monthly; tax and insurance held at today's amounts; property tax applied to the purchase price (actual assessed values differ). Pre-filled defaults are starting points: the latest Freddie Mac PMMS 30-year average rate, a 0.9% property tax rate (average of state effective rates), $1,737/year insurance (NAIC countrywide average) and a 0.5% PMI rate. Change them to match your situation.

Limitations

PMI is shown for the full loan and is not removed automatically once you reach 20–22% equity, although by law it usually can be (CFPB: when PMI can be removed). It does not model adjustable-rate loans, FHA/VA mortgage insurance, local tax exemptions, flood insurance, or rising taxes and premiums over time.

Affordability calculator

Formula

The calculator finds the largest monthly payment your income supports under a debt-to-income (DTI) cap, then converts it into a loan amount:

Max payment = (annual income ÷ 12) × DTI limit − monthly debts

Max payment = P&I + property tax + insurance + PMI

Because property tax depends on the price and PMI applies only when the down payment is under 20%, the calculator solves for the home price directly: with k the monthly principal-and-interest factor per dollar borrowed, t the monthly tax rate and m the monthly PMI rate,

Home price = (Max payment − insurance + down × (k + m)) ÷ (k + m + t)    Loan = Home price − down payment

The "what if" figures re-run the same formula with $200/month less debt, a rate 0.5 percentage points lower, and $10,000 more down.

Assumptions

The DTI limit defaults to 43%, a widely used rule of thumb. Property tax defaults to 0.9% of the price (the average of state effective rates from the Tax Foundation's 2024 data), insurance to $1,737/year (NAIC countrywide average), and PMI to 0.5% of the loan per year when the down payment is under 20%; all three can be changed. The interest rate defaults to the latest Freddie Mac PMMS 30-year average. Actual limits depend on the loan program. Fannie Mae, for example, caps manually underwritten loans at 36% (up to 45% with strong credit and reserves) and allows up to 50% through its automated Desktop Underwriter (Fannie Mae Selling Guide B3-6-02). Where a credit-score range can be selected, an estimated rate adjustment for that range (derived from published rate-by-FICO-score data) is added to the rate you enter. Real pricing varies by lender and is often charged as points instead. Income is gross (pre-tax), as lenders measure it (CFPB: what is DTI).

Limitations

HOA dues and FHA/VA-specific costs (FHA mortgage insurance, the VA funding fee) are not included in the monthly payment. Credit score only enters through the estimated rate adjustment above. The calculator does not check cash reserves or the separate "front-end" housing ratio some lenders use.

Loan payoff calculator

Formula

The number of remaining payments for a fixed-rate loan is:

n = −ln(1 − r × B ÷ PMT) ÷ ln(1 + r)

rounded up to a whole month, where B is the current balance, r the monthly rate and PMT the monthly payment. It is computed once with your regular payment and once with the extra amount added. Interest saved comes from a month-by-month schedule. Each month, interest = balance × r and the rest of the payment reduces principal. The final payment is capped at what is owed.

Assumptions

The extra amount is paid every month starting now and goes entirely to principal. The rate stays fixed. The payment you enter is principal and interest only, without escrow for taxes or insurance.

Limitations

If the payment does not exceed the first month's interest, the loan never pays off and the calculator says so. It does not model one-time lump sums, biweekly schedules, prepayment penalties, or the investment return you give up by prepaying.

Refinance calculator

Formula

• Payments: both the current and new payment use the amortization formula above on your current balance, with the remaining term for the current loan and the new term for the refinance.
• Break-even = closing costs ÷ monthly savings, rounded up to whole months.
• Lifetime savings = (current payment × remaining months) − (new payment × new term in months + closing costs).

The verdict is "likely makes sense" when break-even is 24 months or less and lifetime savings are positive, and "may be worth it" up to 60 months. Beyond that it says "proceed carefully". A lower payment that costs more overall, usually because the term was extended, is never shown as a clear win.

Assumptions

Rate-and-term refinance of the same balance (no cash-out). Closing costs are paid in cash, not rolled into the loan. Remaining term is entered in whole years.

Limitations

The current payment is recalculated from balance, rate and remaining term, so it can differ slightly from your statement. Savings are not discounted for the time value of money, and taxes, PMI changes, points and escrow are not modeled.

Closing costs calculator

Method

Closing costs are built line by line in four groups that mirror the CFPB's Loan Estimate layout:

• Lender fees: an origination fee as a percentage of the loan plus typical flat underwriting, application and credit-report fees. FHA loans add the 1.75% upfront mortgage insurance premium (HUD). VA loans add a funding fee as a percentage of the loan from VA's current funding-fee table, assuming first use: 2.15% with under 5% down, 1.5% with 5% or more, 1.25% with 10% or more.
• Third-party services: appraisal, inspection, title search, lender's and owner's title insurance (each about 0.4% of loan or price, with a minimum), survey, and attorney/settlement fees.
• Government charges: recording fees plus state transfer taxes. Pick a state to apply its state-level transfer or deed tax (including graduated rate bands) and the buyer's customary share of it — all of it where the buyer usually pays, half where custom is split or varies, none where the seller usually pays. Buyer-paid taxes on the mortgage itself, such as New York's mortgage recording tax or Florida's documentary stamp and intangible taxes on the note, appear as their own lines. Rates come from state revenue departments and statutes, compiled in our transfer-tax dataset (as of October 2026). Without a state, a nationwide 0.1%-of-price estimate is used. County and city transfer taxes are not included.
• Prepaids & escrow: one year of homeowners insurance, two months of property tax for the escrow cushion, and about 15 days of prepaid interest.

The total is shown next to the common 2–5%-of-price range so you can see where your estimate falls.

Limitations

Flat fees are national ballpark figures, not quotes. The calculator does not include seller credits, discount points, lender credits or HOA transfer fees. Your lender's Loan Estimate, issued within three business days of applying, is the number to rely on (CFPB: who pays closing costs).

Rent vs buy calculator

Method

A month-by-month simulation over the horizon you pick (5, 10, 20 or 30 years) compares two households:

• Buyer: pays a 30-year fixed mortgage (amortization formula above) plus property tax, insurance and maintenance, all of which grow with the home's value, plus any HOA dues. The home appreciates at your chosen annual rate, compounded monthly.
• Renter: invests the down payment and the buyer's closing costs on day one, and earns your chosen investment return. Each month the renter invests the difference whenever buying costs more than rent, and draws from the portfolio when rent costs more. Rent rises at your chosen annual rate.

Buyer net worth = home value − 6% selling costs − loan balance    Renter net worth = portfolio value

The "break-even" year is the first year the buyer's net worth exceeds the renter's.

Fixed assumptions

Buyer closing costs 3% of the loan; homeowners insurance 0.5% of home value per year; maintenance 1% of home value per year; selling costs 6% of the sale price. The state selector fills in the Tax Foundation property tax rate. Appreciation, rent growth and investment return are user inputs. Their defaults are illustrative, not forecasts.

Limitations

It ignores income taxes (mortgage-interest deduction, capital-gains exclusion on a home sale, tax on investment gains), PMI, renter's insurance and moving costs. The renter's portfolio cannot go below zero. Results are very sensitive to the appreciation and return inputs, so try several scenarios.

State data table

These are the exact values our state selectors use. Property tax: Tax Foundation (2024 ACS data). Insurance: NAIC average HO-3 premium (2023 data).

How we keep data current

• State property tax rates are refreshed when the Tax Foundation publishes its annual update of Census ACS data, usually in the first half of the year.
• State insurance premiums are refreshed when the NAIC releases each new data year of its homeowners report.
• Fee assumptions (FHA and VA fees, DTI guidance) are checked against HUD, VA, Fannie Mae and CFPB pages at each review, and whenever those agencies announce a change.
• The "last reviewed" date at the top of this page changes whenever we check or update the data, and each source above shows its own publication date.

Corrections

If you find a number that looks wrong, a source that has been updated, or a formula that doesn't match what a calculator shows, email valentinzhizajn@gmail.com. Please include the page and the inputs you used. We verify every report against the original source and correct confirmed errors promptly.