About Mortgage R US

Mortgage R US exists to make financial math accessible to everyone. Whether you are sizing up a first mortgage, comparing car loans, or figuring out how long it will take to clear a credit card balance, you deserve straight answers without handing over your email address or your personal data.

Every calculator on this site uses the same industry-standard formulas that banks, lenders, and financial planners rely on — and each one is paired with a plain-English explanation of the math, a worked example, and answers to common questions.

Our loan and mortgage tools use the standard amortization formula that lenders apply to every fixed-rate installment loan:

M = P × r(1 + r)ⁿ ÷ ((1 + r)ⁿ − 1)

where M is the monthly payment, P is the loan principal, r is the monthly interest rate (annual rate ÷ 12), and n is the total number of monthly payments. The mortgage calculator then adds monthly property tax, homeowners insurance, and — when your down payment is below 20% — private mortgage insurance (PMI) to produce a full PITI payment.

Our compound interest calculator uses A = P(1 + r/n)ⁿᵗ + PMT × [((1 + r/n)ⁿᵗ − 1) ÷ (r/n)], and our salary paycheck calculator applies the 2024 federal progressive tax brackets, the standard deduction, and FICA (Social Security 6.2% up to the wage base plus Medicare 1.45%).

Property tax rates are drawn from statewide effective averages published by state revenue departments and aggregated by the Tax Foundation. Mortgage rate context references the Freddie Mac Primary Mortgage Market Survey (PMMS), and demographic and housing data references the U.S. Census Bureau. Federal tax brackets and the Social Security wage base follow IRS and Social Security Administration publications for the 2024 tax year.

Every page is reviewed against three editorial standards: the formula must be transparent and reproducible, the worked example must match the calculator output, and the educational copy must explain the real-world factors — taxes, insurance, PMI, and regional cost variations — that change a borrower's true monthly cost.

Mortgage R US calculators run entirely in your browser. The numbers you type — your salary, your debts, your savings goals — are processed on your own device and are never transmitted to or stored on our servers. There are no accounts to create and nothing to install.

The site is free to use and is supported by advertising. Ads allow us to keep every tool free while continuing to expand the calculator library. Advertising never influences the formulas, the results, or the educational content on any page.

Our tools produce careful estimates for planning and comparison. Real-world figures can differ because of lender fees, local taxes, insurance, and your personal credit profile. Always confirm final numbers with your lender, employer, or a qualified financial professional.

Have a question or a calculator you would like to see next? Get in touch.