The four numbers every rental investor should know
Cap rate (NOI / Price) is the unlevered yield. 5–7% is typical in major US metros; 8%+ is increasingly hard to find without value-add work.
Cash-on-cash return is the levered yield — what your actual down-payment dollars earn each year. Mortgage leverage can lift a 6% cap-rate property to 10%+ cash-on-cash.
DSCR (NOI / Debt Service) under 1.0 means the property doesn't cover its mortgage. Lenders want 1.25+; below 1.0 means you fund the shortfall every month.
The 1% rule (monthly rent ≥ 1% of price) and 50% rule (opex ≈ 50% of rent) are quick filters — they won't replace a real pro forma but they kill bad deals in 30 seconds.