Real Estate Investing Glossary
50% Rule
Last reviewed 2026-07-15
The 50% rule estimates that operating expenses will consume about half of a rental’s gross rent over time, excluding the mortgage.
What is the 50% rule?
The 50% rule is an expense-estimating shortcut: over the long run, expect roughly half of a rental property’s gross rent to go to operating costs, property taxes, insurance, maintenance, capital expenditure reserves, property management, vacancy, and turnover, before any mortgage payment. Whatever remains must cover debt service to produce cash flow.
Its value is defensive. New investors habitually underestimate expenses by counting only taxes and insurance and forgetting vacancy, turnover make-ready costs, management, and the slow drumbeat of capital replacements. The 50% rule forces a realistic baseline in seconds: $1,600 rent means about $800 for expenses, so an $850 mortgage payment signals a money-losing deal, no spreadsheet needed.
Actual ratios vary from roughly 35% for newer homes in low-tax states with owner self-management to 60%+ for older properties in high-tax, high-insurance areas. Use 50% to screen, then replace it with line-item estimates from real tax bills, insurance quotes, and local management pricing before making an offer.
Formula
Estimated operating expenses ≈ 50% × gross rent; estimated cash flow ≈ (gross rent × 50%) − mortgage payment
Worked example
A rental grosses $1,700 per month. The 50% rule budgets $850 for operating expenses, leaving $850. If the principal-and-interest payment is $700, estimated cash flow is $150 per month. If the payment were $950, the screen flags likely negative cash flow.
Frequently asked questions
- Does the 50% rule include the mortgage payment?
- No. The 50% covers operating expenses only, taxes, insurance, maintenance, capex reserves, management, and vacancy. The mortgage comes out of the remaining half. That is the whole point of the rule: it tells you quickly how much rent is truly available to service debt and produce cash flow.
- Why would expenses be anywhere near 50% of rent?
- Because the visible monthly bills are only part of the story. A vacant month every couple of years, $2,000 in turnover costs, a $9,000 roof every two decades, a water heater, an HVAC compressor, and 8-10% management fees all add up. Averaged over a decade of ownership, half of gross rent is a well-documented norm for typical single-family rentals, even though most individual months cost far less.
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