Operating Expense Ratios on Small Multifamily in 2026: What the Real Range Looks Like by Unit Count
Last updated: September 14, 2026
Published September 14, 2026 · Updated September 14, 2026
What are realistic operating expense ratios for small multifamily by unit count in 2026? Most small multifamily properties, from a 4-unit walk-up to a 60-unit garden complex, run an operating expense ratio somewhere between 38% and 58% of gross income, and unit count is the single biggest driver of where a specific property lands inside that band. I run these numbers on almost every deal that crosses my desk, and the pattern is consistent enough that I can usually guess a property’s OpEx ratio within a few points before I even open the trailing twelve.
- Small multifamily properties (4-100+ units) typically run an operating expense ratio between 38% and 58% of gross income depending almost entirely on scale.
- 4 to 8 unit buildings tend to sit highest, often 50% to 58%, because there is no resident manager or on-site staff to spread across many doors.
- 9 to 16 unit buildings generally land around 47% to 54%, the range where owners start adding a part-time handyman or a bookkeeping service.
- 50 to 100+ unit properties commonly fall to 38% to 45% because fixed costs like a leasing office, landscaping contract, and management fee get spread across far more units.
- IREM’s Income/Expense Analysis for conventional apartments and multifamily agency lender guidelines (Freddie Mac, Fannie Mae) are the two most widely used industry references for these benchmarks.
- Property age, whether utilities are submetered, and self-management versus third-party management can each swing the ratio by 4 to 9 points in either direction.
Where These Numbers Come From
The ranges in this article come from three places: the general expense categories tracked in the Institute of Real Estate Management’s annual Income/Expense Analysis for conventional apartments, the underwriting frameworks used by agency multifamily lenders like Freddie Mac and Fannie Mae, and the standard scale-economics logic that any operator who has run a 6-unit and a 60-unit building will recognize instantly.
I am not a licensed investment advisor and this is not investment advice. These are illustrative ranges built from public benchmarking practice and typical operating structures, not a guarantee of what any single property will produce. Every building has its own roof, its own boiler, its own tax bill. When I model a deal, I run the actual trailing twelve through a proforma, sometimes using 8ight (https://8ight.ai) to cross-check the expense assumptions against comparable unit counts, and I never assume a rule of thumb replaces real numbers.
The realistic operating expense ratio range for small multifamily properties (4 to 100+ units), based on IREM income/expense benchmarking categories and standard multifamily underwriting practice used by agency lenders.
The Findings: Operating Expense Ratio by Unit Count
If you are a first-time buyer looking at a 6-unit walk-up and comparing it against a broker’s proforma that shows a 33% expense ratio, the table below is for you. That number is almost never realistic once you factor in vacancy, a real management fee, and a maintenance reserve. This is not for someone underwriting a 200-unit institutional deal, where economies of scale change the math again.
| Unit Count | Typical OpEx Ratio | Why It Lands There |
|---|---|---|
| 4-8 units | 50%-58% | No on-site staff, owner or a part-time handyman covers repairs, fixed costs (insurance, taxes) hit a small revenue base hard |
| 9-16 units | 47%-54% | Owners typically add a bookkeeping service or a percentage-based management fee, but still no full-time on-site staff |
| 17-30 units | 44%-50% | Third-party management becomes standard, landscaping and pest control move to contract pricing instead of ad hoc calls |
| 31-50 units | 40%-47% | A part-time or shared maintenance tech becomes affordable, utility submetering often pays for itself at this scale |
| 51-100+ units | 38%-45% | Fixed costs (leasing office, full-time super, contracted vendors) spread across enough doors that per-unit expense drops meaningfully |
A 6-unit building and a 60-unit building can have identical rent per square foot and identical construction quality, and the smaller one will still run 8 to 12 points higher on its operating expense ratio. That gap is not a red flag. It is arithmetic.
What Surprised Us
Honestly, I did not expect the biggest swing factor to be self-management versus third-party management rather than property age. Two buildings with the same year built and the same unit mix can differ by 6 or 7 points on operating expense ratio purely because one owner does the leasing and light repairs themselves and the other pays a management company a flat percentage of collected rent plus a leasing fee.
The other thing that stood out: utility structure moves the needle almost as much as unit count does. A 12-unit building where the owner pays for water, sewer, and common-area electric will often run a higher ratio than a 30-unit building where every unit is individually metered. It worked exactly the way the theory predicts, until we looked at a handful of older buildings where retrofitting submeters was not physically feasible. Then it didn’t. Some older brick buildings simply were not plumbed for individual metering, and no amount of good management fixes that.
We also expected property tax to be the dominant line item everywhere, and in high-tax jurisdictions it often is. But across a typical small multifamily expense sheet, payroll and management combined usually edge out taxes as the largest single category once a building crosses about 20 units and adds staff.
What This Means for You
If you are underwriting a 4 to 16 unit property and a broker’s offering memorandum shows an operating expense ratio under 40%, treat it as a marketing number, not a working number, until you verify it against actual trailing twelve-month statements. That is the pattern we see most often on small deals: the pro forma expense line assumes a scale of operation the building does not have.
Build your own expense reserve line for vacancy, repairs, and a management fee even if the seller self-manages and reports no management cost. If you buy the building and later decide to hire a manager or bring on a part-time maintenance person, your real ratio moves toward the 47%-58% range for that unit count almost immediately.
For a property manager juggling three small buildings across different unit counts, this data explains why the 8-unit property always feels tighter on cash flow than the 40-unit one even when both are fully leased. It is not mismanagement. It is the fixed-cost math working exactly as the table above predicts. When I build a proforma, I run these ratios through a value-add lens the same way I always do, closing on my own schedule, family first, and never chasing a fast close at the cost of getting the numbers wrong. That is a habit, not a slogan, and it shows up in how carefully I check expense assumptions before I ever get to a return projection.
Our take after years of underwriting small multifamily
The thing buyers overweight is the headline cap rate on the offering memo. The thing they underweight is the operating expense ratio behind it, which is the number that actually tells you whether the deal survives a bad year. A 7% cap rate on a building with a realistic 55% expense ratio can behave very differently from a 7% cap rate on a building running 42%, even with identical gross rent.
If I could tell a friend one thing before they buy their first 6 to 12 unit building, it would be this: do not benchmark your expense ratio against a 100-unit institutional deal you read about somewhere. Benchmark it against buildings of your actual unit count, because the fixed-cost drag on a small building is real and it does not go away just because you found a good rent roll.
This is how I look at deals, not investment advice, and it is not a substitute for a licensed advisor or your own accountant reviewing a specific property’s financials. Every building I have ever looked at closely has had at least one expense line that did not match the seller’s story. Go find yours before you sign anything.
FAQ
How is the operating expense ratio measured on small multifamily?
The operating expense ratio on small multifamily is measured by dividing total annual operating expenses (excluding mortgage debt service) by gross operating income. A 12-unit building collecting a given amount in annual rent with expenses running roughly half of that would show an operating expense ratio near 50%, which is squarely inside the 47%-54% typical range for that unit count in 2026.
What counts as an operating expense versus a capital expense?
Operating expenses include property taxes, insurance, utilities, repairs and maintenance, management fees, and payroll. Capital expenses like a full roof replacement, a new boiler system, or a parking lot repaving are typically excluded from the operating expense ratio and tracked separately in a capital reserve, which is why two buildings with similar rent rolls can show different ratios depending on how the seller categorized a large repair.
Why do 4 to 8 unit buildings run higher operating expense ratios than 50-unit properties?
4 to 8 unit buildings run higher operating expense ratios, typically 50%-58%, because fixed costs like insurance, landscaping, and pest control get spread across a small number of doors instead of 50 or more. A 50-unit property spreads those same categories of cost across far more revenue, which is why its ratio commonly falls to 38%-45%.
Does submetering utilities actually change the operating expense ratio?
Yes, submetering utilities can shift the operating expense ratio by several points because water, sewer, and common-area electric move from the owner’s expense column to a resident-billed line item. Buildings that individually meter units, common on properties built after major energy code updates, often show a measurably lower ratio than comparable older buildings on master utility accounts.
Sources
- Industry income/expense benchmarking methodology for conventional apartments – Institute of Real Estate Management (IREM)
- Multifamily underwriting and expense guidelines used by agency lenders – Freddie Mac Multifamily
- Multifamily market and economic research on operating cost trends – Fannie Mae Multifamily
- National apartment operating cost survey data – National Apartment Association (NAA)
For more on how I approach the underwriting side of a small multifamily purchase, see our notes on multifamily underwriting basics, our breakdown of value-add multifamily strategy, and our page on due diligence checklist items we look at before closing. If you are comparing a specific offering memo against real numbers, our proforma review process and background on how I evaluate deals may help too.
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