Methodology

Every figure on this site comes from one of a few formulas applied to a published average. This page lists them, with every assumption.

Monthly payment

For a loan of P at annual rate r over n months, with monthly rate i = r / 12:

payment = P × i / (1 − (1 + i)⁻ⁿ)

At 0% the payment is simply P / n. The schedule applies each month's interest (balance × i) and puts the rest of the payment toward principal. We keep full precision throughout and round only for display, so the schedule's totals equal the formula's totals to the cent and the last balance is exactly zero. Published calculators sometimes round the payment first; that can change 30-year total interest by about a dollar.

Which average each page uses

• Mortgage and house pages: Freddie Mac PMMS 30-year average (7.03%, week of September 24, 2026); 15-year average for 15-year rows. Freddie Mac no longer surveys 20-year loans, so 20-year rows use the 30-year average, which slightly overstates their cost.
• Car loans: the Fed's commercial-bank average for 48-month new-car loans for 36 and 48 months, and for 60-month loans for 60, 72 and 84 months. No survey covers 72- or 84-month loans; they usually cost more than this.
• Personal loans: the Fed's commercial-bank 24-month average for every term. Online lenders often charge more.
• Student loans: the 2026-27 federal undergraduate rate; graduate and PLUS rates in tables.

Taxes, insurance and PMI

• Property tax: the state's median effective rate (median taxes paid ÷ median home value, Census ACS via the Tax Foundation) times the price, divided by 12. For states we have not yet sourced, and when no state is chosen, we use the median of the sourced state rates and label it an estimate.
• Homeowners insurance: the NAIC average premium for the state where we have a sourced figure. Elsewhere insurance is left out and the page says so; we would rather show a smaller, labelled total than invent a number.
• PMI: 0.75% of the loan a year when the down payment is under 20%, the middle of the 0.5–1.5% range published by the Urban Institute and Freddie Mac. It stops in the month the scheduled balance reaches 78% of the original price (automatic termination under the Homeowners Protection Act), or at the midpoint of the term at the latest.
• Loan-amount pages don't know the purchase price, so their tax figure assumes the loan is 80% of the price.

Affordability

House: the monthly budget is the lower of 28% of gross monthly income and 36% minus your other debt payments. The maximum price is the one whose full payment (principal, interest, tax, PMI and insurance where sourced) equals that budget; because the payment is linear in the price, it is solved exactly. Car: the payment is 10%, 15% or 20% of gross monthly income; the loan it supports is found by inverting the payment formula, and the price adds back a 10% down payment and, if you choose a state, its sales tax.

Sales tax on cars

State rate times the price, minus the trade-in where the state allows it (Michigan caps the credit at $12,000 in 2026). Tax is assumed to be financed with the car. Local sales taxes are not included. Only states whose rules we verified are offered.

What these numbers are not

They are not quotes. Averages describe the middle of the market for a typical borrower in the survey; the rate a lender quotes depends on credit, down payment, points, loan type and lender. Payments exclude HOA dues, closing costs, points, dealer fees, registration and origination fees unless stated.