Operating Expense Ratio
How much of the rent never reaches you
The operating expense ratio is the share of gross rental income consumed by operating costs such as taxes, insurance, water, maintenance, turnover, management, and vacancy. On older Philadelphia multifamily buildings a realistic ratio is 40 to 50 percent, far higher than the optimistic numbers in most listing pro formas.
Expense Ratio = Operating Expenses ÷ Gross Rental Income × 100- Operating Expenses
- All costs to run the building, excluding the mortgage
- Gross Rental Income
- Total market rent from all units over twelve months
Example: A duplex collecting $36,000 a year with $16,200 in operating costs runs a 45 percent expense ratio, leaving $19,800 of NOI.












