The expense ratio is operating expenses divided by effective gross income.
That is it. If a property has $1,000,000 of EGI and $470,000 of operating expenses, the expense ratio is 47%.
$470,000 / $1,000,000 = 47%
The ratio tells you how much collected operating income the property uses to keep operating before debt service and capital events. It is useful because an oddly low, high, or suddenly improving number tells you where the story needs to come apart.
It does not tell you whether the story is true. A gauge can show low pressure. It cannot tell you whether the system got efficient or somebody disconnected the sensor.
What the ratio can and cannot tell you
| It can help you spot | It cannot prove |
|---|---|
| Expenses that look underwritten too low | That the property is well run |
| A tax or insurance miss | That NOI is durable |
| A strange shift from historicals | That the business plan is realistic |
| A need for line-item review | That a deal is good or bad |
That distinction matters because people love turning a diagnostic into a trophy. They ask whether 43% is “good” before asking what is inside the 43%.
Property type, age, location, utility responsibility, staffing, service level, revenue mix, and accounting treatment all affect the result. Two properties can post the same ratio while one is maintained well and the other is borrowing from next year’s repair budget.
The ratio points. The general ledger explains.
A quick range check
Imagine a 72-unit property:
| Line | Amount |
|---|---|
| EGI | $936,000 |
| Historical operating expenses | $505,000 |
| Historical expense ratio | 54.0% |
| Pro forma operating expenses | $430,000 |
| Pro forma expense ratio | 45.9% |
Maybe the operator has a real plan. Maybe the seller was sloppy. Maybe taxes and insurance are about to punch the model in the mouth.
The move from 54.0% to 45.9% is not proof of improvement. It is a work order. Every reduction needs a named expense line, a source, an owner, and a date when the savings begin.
If the plan cannot explain the movement line by line, the ratio did its job. It found the loose connection.
The suspicious improvements
I get interested when the model improves the ratio by:
- Lowering repairs while also planning renovations.
- Lowering payroll while promising better leasing.
- Holding insurance flat in a difficult market.
- Using old taxes after a sale.
- Growing EGI fast while management costs stay weirdly calm.
Each claim may be possible. None earns trust by fitting neatly in a pro forma. Pull the T-12, monthly general ledger, current tax bill, insurance quote, payroll plan, utility bills, vendor contracts, and management agreement.
Expense ratios often look best during the short interval between the pitch and the document request.
Run three gauges, not one
Calculate three ratios:
| Version | Formula |
|---|---|
| Seller historical | T-12 expenses / T-12 EGI |
| Sponsor year one | Modeled year-one expenses / modeled year-one EGI |
| Your stress case | Your adjusted expenses / your adjusted EGI |
If the sponsor’s ratio is much cleaner than both the historical and your stress case, require line-item proof. “Efficiency” is not proof. It is what people write on the tag after removing a part they hope nobody needed.
Do not compare the percentages alone. Build a bridge showing which income and expense assumptions create each change. A lower ratio caused by higher, unsupported EGI is not operating skill. It is a larger denominator doing public relations.
Questions that make “good” useful
Before accepting the benchmark, ask:
- Does the historical ratio reconcile to the T-12 and general ledger?
- Which three line items explain most of the change to year one?
- Are taxes and insurance based on current post-sale evidence?
- Did repair costs fall because the property improved, or because work was deferred?
- Does the staffing plan support the payroll number and the promised service level?
- What happens to the ratio if EGI misses while expenses rise?
Watch for ratios that exclude ordinary operating costs, mix capital spending into repairs, compare different property types, or use periods with different accounting. A precise percentage built from inconsistent parts is still miscalibrated.
Use the ratio as a diagnostic
Calculate the seller historical, sponsor year-one, and your stress-case ratio. Then use the difference to choose the next five expense lines to inspect. Do not argue about whether a percentage is “good” until taxes, insurance, payroll, utilities, and repairs have source documents beside them.
The winning number is not the lowest ratio. It is the one you can trace without anyone reaching for an adjective.
PR Steinfurth Equity provides educational information only. Nothing on this website is an offer to sell or a solicitation of an offer to buy any security, nor investment, legal, or tax advice. Any securities offering is made only to qualified investors through official offering documents. Real estate investments involve risk, including possible loss of principal. Past performance is not indicative of future results.