How Do Apartment Complexes Make Money?

An apartment complex makes money in three ways: monthly cash flow, paying down its loan, and any gain when the building is sold or refinanced. Cash flow is rent plus other income such as fees and utility reimbursements, minus vacancy, minus operating expenses (taxes, insurance, payroll, repairs, utilities, management), minus the loan payment. Because expenses and debt take most of the income, a few points of occupancy, a tax reassessment or a rate change can swing the owner's profit from healthy to near zero.

This guide walks through each line of a full-year budget for a hypothetical 60-unit building, shows how the owners' money is made and lost, and points to deeper guides on each piece.

Where does an apartment complex's income come from?

Start with what the building could collect and work down to what it does collect.

• Gross potential rent (GPR): every unit leased at its rent for 12 months.
• Vacancy, concessions and bad debt: empty units, free-rent specials and rent that is billed but never paid. Together these are the gap between physical and economic occupancy; see economic vs. physical occupancy.
• Utility reimbursement: water, sewer and trash billed back to residents, often through a ratio utility billing system; see RUBS.
• Other income: parking, pet rent, application and late fees, laundry, storage.

The result is effective gross income (EGI), the money actually collected.

Where does the money go?

Operating expenses are the costs of running the building, before any loan:

• Property taxes, often the largest line and the one most likely to jump after a sale, when many places reassess the building at its new price.
• Insurance.
• Payroll for on-site staff.
• Repairs and maintenance, including turning units between residents.
• Utilities the owner pays, such as common-area power and any water not billed back.
• Management fee, usually a percentage of collected income.
• Administrative, marketing and contract services such as landscaping and pest control.
• Replacement reserves, money set aside for roofs, HVAC and appliances.

NOI = EGI minus operating expenses. Then comes debt service, the year's principal and interest on the loan. What is left is cash flow before tax, the money available to distribute to owners.

We do not quote an industry-average expense ratio here, because we could not load a published benchmark to cite. Use the property's own trailing 12 months (T-12) of income and expenses instead.

A 60-unit pro forma that adds up

A 60-unit building rents at an average of $1,300 a month and is bought for $7,200,000 with a $5,040,000 loan (70% of the price) at 6.5% on 30-year amortization. All numbers are hypothetical, for illustration only.

Check the math: $936,000 - $65,520 + $36,000 + $24,000 = $930,480. The expenses sum to $461,219. $930,480 - $461,219 = $469,261. $469,261 - $382,275 = $86,986.

Three ratios come out of this table:

• Cap rate at purchase: $469,261 / $7,200,000 = 6.5%.
• Debt service coverage: $469,261 / $382,275 = 1.23x.
• Cash yield on equity: if owners put in $2,310,000 (the $2,160,000 down payment plus $150,000 of closing costs), $86,986 / $2,310,000 = 3.8%.

The loan payment also includes about $56,000 of principal in year 1, which builds equity but is not cash in anyone's pocket until a sale or refinance.

How much money does an apartment complex make in a bad year?

Same building, but vacancy and concessions rise to 12%, and taxes and insurance rise by a combined $32,000. All numbers are hypothetical, for illustration only.

How it works: 12% of $936,000 is $112,320, so EGI is $936,000 - $112,320 + $60,000 = $883,680. Management falls to $35,347 (4%), and expenses become $461,219 - $37,219 + $35,347 + $32,000 = $491,347. Income fell 5%, but cash flow fell 88%. That is leverage at work, and it is why distributions can be cut even when a building is still mostly full. For the occupancy at which cash flow hits zero, see break-even occupancy.

Where does the rest of the profit come from?

From the sale or a refinance. A buyer pays a price set by NOI and the cap rate, and the owners keep what is left after the loan and selling costs. Two hypothetical year-5 sales of the same building (hypothetical, for illustration only; the loan balance after 5 years is about $4,717,993 and selling costs are 2% of the price):

In the base case the owners get back more than they invested, before counting the cash flow along the way. In the weak case they lose about 39% of their capital at the sale, and in a typical syndication the investors bear that loss, because the sponsor's share of sale profit only starts after investors get their capital back. Cap rates at exit are not under anyone's control; see exit cap rate assumptions. And in a syndication the cash is then shared by the waterfall, explained in how syndication investors get paid.

What can go wrong?

• Vacancy and bad debt run above plan, especially when new buildings nearby offer concessions.
• Taxes and insurance rise faster than rents.
• Floating-rate debt resets higher, or a fixed loan matures into a higher rate.
• Renovation costs run over, or upgraded units do not get the planned rent.
• Cap rates rise between purchase and sale, cutting the price even if NOI grew.
• Big repairs exceed reserves and force a capital call or a cut in distributions.

To test a deal, change one of these at a time in the sponsor's model and watch cash flow and the sale proceeds. Multifamily underwriting basics shows how to stress test NOI, cap rate and DSCR.

How DoorRaise fits in

DoorRaise lets sponsors raise equity for apartment buildings with 5 or more units from their friends and followers, with verified accredited investors. It does not underwrite the deal or predict its income: the pro forma is the sponsor's. DoorRaise forms the deal's LLC, prepares the offering documents, files Form D and verifies accreditation for 506(c) deals. Investors fund by wire into escrow at Enterprise Bank & Trust, an FDIC-insured bank, and distributions are quarterly by default. Fees are $1,500 to set up (non-refundable), $5,000 at closing (only if the deal closes) and $3,500 a year.

Run your own numbers with the apartment deal calculator, or see pricing.

FAQ

How do apartment complexes make money?

From rent and other income, minus vacancy, operating expenses and the loan payment, which leaves cash flow; from paying down the loan; and from any gain when the building is sold or refinanced.

How do apartment building owners make money?

The same way, with one addition in a syndication: the sponsor who runs the deal earns fees and a share of profit, and passive investors receive distributions from cash flow and a share of the sale proceeds.

How profitable are apartment complexes?

It varies widely by price, debt, market and management. In our hypothetical 60-unit example, cash flow is about 3.8% of the owners' money in a normal year and close to zero in a bad one, and the sale can return more or less than was invested.

How much money does an apartment complex make a year?

Take the effective gross income, subtract operating expenses for NOI, then subtract the loan payment. In the example, a building collecting $930,480 a year has NOI of $469,261 and cash flow of $86,986.

What percentage of rent goes to expenses?

It depends on the building, its age, taxes and who pays utilities. In the example, operating expenses are 49.6% of collected income. Use the property's own T-12 rather than a rule of thumb.

Sources

The figures in this article are a hypothetical example and use no outside data. For the definitions and lender tests behind NOI and DSCR, see:

• Fannie Mae Multifamily Selling and Servicing Guide, Underwritten DSCR and glossary (effective October 26, 2026)
• IRS Publication 527 (2025), Residential Rental Property

This article is general information, not legal, tax or investment advice. Every investment can lose money. DoorRaise is not a law firm, broker-dealer, investment adviser or funding portal.