Max home price you can actually afford. Uses 28% front-end + 43% back-end DTI (whichever binds first), real lender math, plus recommended 6-month PITI reserves.
Lenders evaluate two ratios: front-end (housing-only payment ÷ gross income, traditionally capped at 28%) and back-end (housing + all other monthly debt ÷ gross income, traditionally 36%, extended to 43% under QM rules). Both have to clear. This tool computes the maximum home price a lender would actually approve, using both ratios — whichever binds first.
For high-income buyers with little other debt, the 28% front-end ratio binds first — only an income increase moves it. For buyers carrying student loans plus a car payment, the 43% back-end ratio binds first — paying down debts unlocks more budget. This is why 'I can save $5K/month' and 'a bank will approve $5K/month for me' are different numbers.
This tool sizes the loan only. A full Nestlyze run layers the candidate property's real tax, insurance, HOA, and forecasted 7-year system-replacement costs on top to show what's actually sustainable. Reserves rule of thumb: 6 months of PITI in cash on top of down payment.