The 50% rule says that operating expenses on a rental typically consume about half of gross rent, before the mortgage. It is a back-of-the-envelope check that forces you to budget for management, maintenance, taxes, insurance and vacancy instead of assuming rent is profit.
The rule is a screening heuristic, not a law. High-tax or older properties can run well above 50%; newer, low-tax properties can run below it. RentScope computes your actual operating-expense ratio so you can compare it with 50%.
Formula
50% rule: Operating expenses ≈ 50% of gross rent
Operating expenses here include management, maintenance, property taxes, insurance, HOA dues, owner-paid utilities and a vacancy allowance. The mortgage is separate. If your actual expense ratio is below 50%, the rule is conservative for your deal; if it is above, the rule would understate your costs.
How to calculate it
- Take annual gross rent.
- Estimate total operating expenses (not including the mortgage).
- Divide expenses by gross rent to get your operating-expense ratio.
- Compare it to 50%. If it is far above, look closely at taxes, insurance and maintenance.
Worked example
Assume a $250,000 property renting for $2,000/month with typical expenses and a 7.00% loan. Running those numbers through the RentScope engine gives:
Open the free calculator with your own numbers →
FAQ
Is the 50% rule accurate?
It is a rough average across many properties. It is most useful as a quick filter; always replace it with actual numbers before making an offer.
What expenses does the 50% rule include?
Management, maintenance, taxes, insurance, HOA, utilities and vacancy. It does not include the mortgage.
When does the 50% rule fail?
It understates costs for old or high-tax properties and overstates them for newer, low-expense properties. It also ignores the timing of capital expenditures.
What is a good operating-expense ratio?
Lower is better, but a very low ratio can mean maintenance or capital expenditures are being deferred. A ratio near or below 50% is generally healthy for a long-term rental.
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