The strict term for the fee base in most multifamily management agreements is effective gross income, sometimes written as gross collected receipts. That means rent actually collected plus other income actually collected: pet rent, parking, storage, utility reimbursements, application and late fees. The loose market usage is "gross revenue," which people say when they mean the same thing, so read the definition clause rather than the headline percentage. Well-drafted agreements exclude security deposits, insurance proceeds, and sale or refinance proceeds from the base, and they say whether the fee is calculated on billed or collected amounts. On billed, you get paid on delinquency you never banked.
The percentage is lower on apartments because the base is much larger. At 180 units and $1,500 average rent you're looking at roughly $3.2 million a year of rent before other income, so 3.5% is a real fee. On an eight-unit building the same percentage wouldn't pay for a phone line, which is why small-portfolio work is priced at 8 to 10% and often carries a monthly minimum per door.
The part that surprises people coming from single family: on-site staff at an apartment community are almost always paid out of the property's operating account, not out of your fee. The manager, the leasing agents, the maintenance techs, their benefits and payroll taxes, those sit in the owner's budget. Your 3.5% covers the management company, supervision, accounting, and reporting. Check which software licenses, marketing costs, and construction management work are inside the fee and which are reimbursed, in writing, before you sign.
