The big four numbers
Buying a home comes down to four numbers: monthly payment (principal, interest, taxes, insurance, plus PMI below 20% down), affordability (what your income and debt-to-income ratio support), down payment (cash needed up front), and equity (the slice of the home you actually own as principal pays down and the home appreciates). Each calculator on this hub focuses on one of those four — together they cover the full pre-purchase picture.
How much house can you afford
Start with Home Affordability to find your ceiling. It applies the standard 28/36 rule (housing under 28% of gross income, total debt under 36%) plus the actual debt-to-income limits lenders use, so the number you get is closer to what an underwriter would actually approve than a back-of-envelope multiple of your salary.
Down payment, PMI, and equity
The Down Payment Calculator shows how the size of your down payment affects loan amount, monthly cost, and whether you need to pay private mortgage insurance. Below 20% down, PMI typically adds 0.3–1.5% of the loan balance per year. The Home Equity Calculator tracks the other side: how equity grows from principal payments and home appreciation over time, including a year-by-year split between the two.
Rent vs. buy
Rent vs. Buy answers the longer-horizon question. It compares the full lifetime cost of buying (down payment, closing costs, mortgage payments, taxes, insurance, maintenance, opportunity cost of the down payment) against renting (rent + opportunity cost on the avoided down payment). It's the right tool for deciding whether to buy at all, whereas the mortgage payment calculator answers "given that I'm buying, what does it cost per month?" via the Mortgage Payment Calculator.
Once you have a mortgage
Two calculators take over after closing. The Mortgage Refinance Calculator compares your current loan to a new one, surfacing monthly savings, the closing-cost break-even month, and lifetime interest difference — the three numbers that determine whether refinancing actually pays off. The Mortgage Extra Payment Calculator models the other path to lower lifetime interest: paying extra principal — recurring monthly, an annual lump sum, or a one-time payment — and reports exactly how much time and interest you save.
Related categories
Auto and personal loans use the same amortization math — see Loan Calculators for non-mortgage debt, and Amortization Schedule for a full month-by-month breakdown of any loan, including a mortgage. For long-term wealth-building tools, see Savings & Investing.