Free tool · before a big purchase
Big-Purchase Affordability Estimator
Approved is not the same as affordable. A lender tells you the most they will lend, measured on gross income and counting the debts on your credit report plus the cost of the loan itself — a good model of a lender's risk and a poor model of yours. This free spreadsheet runs the first of the three tests in the full workbook: the debt-to-income ceiling, for a home purchase. It takes your gross monthly income times a conservative debt-to-income cap, subtracts every payment you already owe, and turns what's left back into a purchase price through the loan's own payment factor. It returns your debt-to-income ratio today, an estimated maximum price, the all-in monthly cost at that price, and the cash you'd need at the table. It opens pre-filled with a worked example, so you can see the shape of the answer before you type anything.
Take it with you — free, no signup
Direct download. No email, no account — just the files.
What it does
- Turns a monthly payment budget into a maximum purchase price through the loan's own payment factor — with your existing payments subtracted first, which is the step that changes the answer most.
- Counts property tax, insurance, dues and upkeep in the monthly cost of the purchase — including the upkeep a lender's qualifying payment leaves out. It does not add mortgage insurance separately, so raise the ownership-cost percentage if you're putting down less than 20%.
- Shows your debt-to-income ratio as it stands today, judged against the cap you set, next to the price that cap still leaves room for.
- Prices the lever both ways: how much purchase price each $1 a month of existing debt payment is holding down.
- Reports the all-in monthly cost at your ceiling — split into loan payment and ownership costs — and the cash you would need at the table to reach it.
- Uses a conservative debt-to-income cap rather than the wider limits lenders will underwrite to, and says plainly which is which.
- Opens pre-filled with a complete worked example you overwrite with your own numbers.
Related reading
Own it, don't rent it
Want the other two ceilings — and to know which one is really stopping you?
This free tool computes one of three ceilings, for one purchase type. The full workbook computes all three — what your income will carry, what your cash can actually reach after protecting an emergency reserve, and whether the purchase is a sensible size for what you earn — takes the smallest, and names which one is binding, so you know which lever is worth pulling and which is worth nothing. It adds six purchase types with their own curated financing, ownership-cost and reserve rules, a twelve-rung price ladder that costs every price point with a Comfortable / Stretch / Over verdict, and eight wait-and-save scenarios that each re-solve the whole model. Eight connected tabs (Excel, Google Sheets, or LibreOffice) and five guides, one of them a set of printable worksheets to take into the room.
A one-time purchase you keep and reuse on the next big decision, and the one after that. No subscription, no lead form, and it works offline.
A financial planning aid, not licensed financial, tax, lending, or legal advice, and not an offer of credit or a prediction that you will be approved for anything. Every figure that ships in the file is an illustrative example for a household that does not exist, and the caps and costs it uses are planning conventions, most of them cells you can edit — they vary by lender, loan program, credit profile, and market. Confirm what matters with your lender.