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Operating expense ratio calculator
See what share of a rental’s income goes to running it. Operating expense ratio is operating expenses divided by gross operating income. Enter both for an estimate from your numbers.
The short answer
Last updated: July 2026
Operating expense ratio (OER) is a rental’s annual operating expenses divided by its gross operating income, shown as a percentage. It reveals how much of the income running costs consume before the mortgage. $9,000 of expenses on $31,200 of income is an OER near 29%. Lower means more income survives. This estimate uses your inputs.
After the estimate:
Self-management softwareOperating expense ratio calculator
What share of income the running costs eat.
Operating expense ratio is annual operating expenses divided by gross operating income. Enter both to estimate the share of income spent running the property.
Annual operating expenses (excl. mortgage)
$
Taxes, insurance, management, repairs, vacancy — everything but loan payments.
Gross operating income
$
Annual rent collected plus other income, after an allowance for vacancy.
Input-driven result
Your inputs
Formula
Result below
Operating expense ratio
28.8%
Expenses $9,000 ÷ income $31,200.
Net operating income (NOI)
$22,200
Income minus operating expenses — the income left before the mortgage.
Operating income composition
Gross operating income
$31,200
Operating expenses
-$9,000
Net operating income
$22,200
Estimate based on your inputs. Not a promise of results.
Estimate only. A lower ratio means more income survives operating costs, but the "right" ratio depends heavily on property age, location, and how expenses are categorized. Compare like with like.
How it works
How this tool works.
Operating expense ratio tells you how efficiently a property runs. It’s the share of gross operating income consumed by operating costs — taxes, insurance, management, repairs, and vacancy — before any mortgage. A lower ratio means more of each rent dollar survives to become net operating income.
Enter annual operating expenses and gross operating income, and this calculator estimates the ratio along with the NOI behind it. It’s arithmetic on your numbers, useful for comparing properties measured the same way.
Make the result useful
Operating-expense-ratio analysis
Operating expenses are recurring property costs before financing.
Effective gross income is income after vacancy/concessions on a stated basis.
Mortgage debt and capital projects should not be mixed into a recurring OER.
Compare the same period and accounting basis across properties.
Calculation lens
operating expense ratio = operating expenses ÷ effective gross income
Use the output as a documented scenario result, not a guarantee.
Does not measure debt service, capital needs, or property value.
Questions landlords ask
Questions about this tool and its limits.
Built by a landlord who's done every one of these jobs by hand.
Aptoria was built by an owner-operator managing a Brooklyn portfolio — the 11pm calls, the awkward rent texts, the April receipt-pile — not by a software team guessing at the problem.
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