Operating Expense Ratio Calculator Formula
Understand the math behind the operating expense ratio calculator. Each variable explained with a worked example.
Formulas Used
Operating Expense Ratio
oer = (operating_expenses / gross_income) * 100Net Operating Income
noi = gross_income - operating_expensesNOI Ratio
noi_ratio = ((gross_income - operating_expenses) / gross_income) * 100Variables
| Variable | Description | Default |
|---|---|---|
operating_expenses | Total Operating Expenses(USD) | 22000 |
gross_income | Effective Gross Income(USD) | 55000 |
How It Works
Operating Expense Ratio
The OER shows what percentage of a property's gross income is spent on operating costs. A lower OER indicates more efficient property management.
Formula
OER = Operating Expenses / Effective Gross Income x 100
Benchmarks
Worked Example
A property has $22,000 in operating expenses on $55,000 effective gross income.
- 01OER = $22,000 / $55,000 x 100 = 40.0%
- 02NOI = $55,000 - $22,000 = $33,000
- 03NOI ratio = $33,000 / $55,000 x 100 = 60.0%
- 04A 40% OER means 40 cents of every income dollar goes to expenses
Frequently Asked Questions
What is a good operating expense ratio?
It depends on property type. For residential rentals, 35-45% is typical. Lower is better, but unusually low OER may indicate deferred maintenance. Higher OER reduces NOI and investor returns.
What counts as an operating expense?
Operating expenses include property taxes, insurance, management fees, repairs, maintenance, utilities (if owner-paid), landscaping, and reserves for replacements. Mortgage payments are excluded.
How can I reduce my OER?
Increase rents to boost income, renegotiate service contracts, implement energy efficiency improvements, appeal property taxes, and reduce vacancy to spread fixed costs over more income.
Ready to run the numbers?
Open Operating Expense Ratio Calculator