Works backward from your income and debts to a maximum price, using the lender's 28/36 debt-to-income rules — with the ratios adjustable.
Before taxes, including both earners on a joint application.
Car loans, student loans, credit-card minimums — not rent or utilities.
PMI applies only while the down payment is under 20% of the price.
28/36 is the classic conservative rule. Many lenders will approve up to 43–50% back-end — that doesn't make it comfortable.
Every point on this curve uses your income, debts, and down payment — only the rate changes. The dot is today's rate.