Calculator Methodology

The calculator uses a fixed-rate amortization formula for principal and interest. It adds taxes, insurance, PMI, HOA, maintenance reserve, utilities, and extra principal to estimate true monthly cost.

Monthly P&I = P × [r(1+r)^n] / [(1+r)^n − 1]

True monthly housing cost = P&I + taxes + insurance + PMI + HOA + utilities + maintenance reserve

Risk labels are educational cash-flow signals, not underwriting decisions.