Rental Expense Ratio Calculator
OER · Cost breakdown · Benchmark analysis
~1% of property value
~8–10% of collected rent
If landlord-paid
Estimated lost rent
HOA, legal, accounting
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Operating Expense Ratio
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Annual NOI
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Rating
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Expense Per Unit/Mo
About This Calculator
The Operating Expense Ratio (OER) measures what percentage of your gross rental income goes toward operating expenses. It's a critical benchmarking tool for landlords and property managers.
Formula: OER = Total Operating Expenses ÷ Gross Rental Income × 100. A well-run residential property typically has an OER of 35–45%. Above 50% indicates potential inefficiencies or underpriced rents. Below 35% may mean deferred maintenance.
Note: OER does NOT include mortgage payments (debt service) — those are financing costs, not operating expenses. This makes OER useful for comparing properties regardless of how they're financed.
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Frequently Asked Questions
What is a good operating expense ratio for rental property?▼
For residential rentals, a 35–45% OER is considered healthy. Commercial properties typically run 35–50% OER. An OER above 55% warrants investigation — either rents are below market, expenses are out of control, or both. Below 30% may indicate deferred maintenance.
Does OER include mortgage payments?▼
No. Operating Expense Ratio only includes operating expenses (taxes, insurance, maintenance, management, utilities). Mortgage payments are debt service and are excluded from OER analysis. This makes OER useful for comparing properties regardless of financing.
What is the 50% rule for rental expenses?▼
The 50% rule is a quick estimate that says operating expenses (excluding mortgage) will equal approximately 50% of gross rent. While not precise, it's useful for quick deal screening. If you collect $2,000/month in rent, budget $1,000/month for operating expenses before the mortgage.
How can I reduce my rental expense ratio?▼
Increase rents to market rate (most impactful), reduce vacancy through better tenant retention, self-manage to eliminate 8–10% management fees, preventive maintenance to avoid costly emergency repairs, shop insurance annually, and contest property tax assessments when overvalued.
How does OER affect property value?▼
In commercial real estate, property value = NOI ÷ Cap Rate. A lower OER = higher NOI = higher property value. Reducing annual expenses by $5,000 on a property with a 5% cap rate increases value by $100,000. This is why experienced investors focus heavily on expense control.
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