How it works

Same math a careful spreadsheet uses. No locked results.

Start on the calculator. Change any input and the verdict updates immediately. Nothing is sent to a server.

1. Mortgage payment

Principal and interest only. Taxes and insurance are separate line items so you can paste the real bills.

2. Effective income

Gross rent plus other income, then minus vacancy. Default vacancy is 7% — about 3–4 empty weeks a year.

3. Operating costs

Property tax, insurance, HOA, owner-paid utilities, management, maintenance, and a capex reserve. Capex is included in cash flow on purpose. Optimistic calculators hide that row and deals look better than they are.

4. What you keep

NOI is income after operating costs, before the mortgage. Cash flow is NOI minus P&I. Cash-on-cash is annual cash flow divided by money you actually put in (down payment + closing + rehab).

5. Verdict

• Buy — cash flow at least $150/mo, cash-on-cash at least 6%, DSCR at least 1.20
• Thin — cash flow is zero or better, but returns or coverage are tight
• Pass — negative cash flow after reserves

Those cutoffs are screening rules, not a commandment. Read assumptions and the disclaimer.