What this multifamily calculator measures
A multifamily deal is a stack of leases, not a single rent. Vacancy, loss-to-lease, and operating costs hit the building before the loan is paid. This multifamily calculator shows six headlines from that stack: year-1 cash flow, cap rate, equity, the monthly loan payment, DSCR, and price per unit.
The free inputs are purchase price, 1-bedroom rent, and 2-bedroom rent. The sample building is six 1-bedrooms and four 2-bedrooms. If your building is a triplex, the headlines are the wrong shape until you open the full unit mix and type the real counts. Changing price scales the 75% loan.
The paid calculator adds the five-year pro forma, a full expense list, and IRR. The free page is year one of the same engine.
Formula
Gross potential rent adds each unit type: count times monthly rent times twelve. The sample is 6 times the 1-bedroom rent plus 4 times the 2-bedroom rent. Vacancy and loss-to-lease come off that potential. Other income, utility reimbursement, and laundry stay on the defaults. Effective income is what remains. Operating expenses are the default lines for taxes, insurance, repairs, utilities, and the smaller recurring items, plus a management fee percent. NOI is effective income minus operating expenses.
Reserves are a per-unit amount. Debt service comes from the loan. On the free page the loan principal is 75% of the purchase price you type, at the sample rate of 6.75% and a 30-year term, because 75% of the $1,200,000 default is the $900,000 loan the engine ships with. Year-1 cash flow is NOI minus reserves minus debt service. Cap rate is year-1 NOI divided by the purchase price.
Equity is the cash you still put in after the loan and the closing costs. Closing costs on the sample include the acquisition fee, origination, lender reserves, legal, title, and miscellaneous closing. They do not scale with price, so a much cheaper building can show closing costs that are too heavy.
Example
Worked example
Illustrative example. The unit rents, cap rate, and cash flow below are a sample building. They are not a property this company manages.
The multifamily sample is a $1,200,000 purchase with six 1-bedroom units at $1,150 and four 2-bedroom units at $1,450. Occupancy is 95%. Loss-to-lease is 1%. The loan default is $900,000 at 6.75% for 30 years, which is 75% of the purchase price. When you change the purchase price in the free calculator, the loan stays at 75% of the new price and the property value used for that loan moves with it. Closing lines stay on the defaults: acquisition fee $12,000, origination $9,000, lender reserves $4,000, legal $6,000, title $4,500, and miscellaneous closing $2,000. Year-1 cash flow is $35,653. Cap rate is 9.06%. Equity is $337,500. Unit count on the untouched sample is 10.
Lower both rents and cash flow, cap rate, and DSCR fall together while equity barely moves. Lower the price and the loan and payment shrink with it, but closing costs stay put.
Price per unit and cost per door
Investors often compare buildings per unit, also called per door. The free calculator prints price per unit. Price per unit is the purchase price divided by the unit count. Equity per unit is the equity headline divided by the unit count. On the 10-unit sample that is $120,000 of price per unit, $33,750 of equity per unit, and about $3,565 of year-1 cash flow per unit.
Per-door figures are a quick screen, not a value. Two buildings at the same price per unit can have very different rents and expenses.
Renovation cost per unit is not on this page; use the rehab cost guide linked below.
Multifamily mortgage payment and DSCR
The sample loan is $900,000, 75% of the price, so the down payment is $300,000 before closing costs. At 6.75% for 30 years, principal and interest are $5,837 a month, or $70,049 a year. Taxes and insurance sit in operating expenses, inside NOI.
DSCR, the debt service coverage ratio, is year-1 NOI divided by the year's loan payments: $108,702 divided by $70,049, or 1.55x. At 1.00x the income just covers the loan.
Lenders set their own minimum DSCR. Take 1.20x, the full calculator's starting target, as an example only, not a lender rule. At 1.20x the sample NOI would support a loan of about $1.16 million at the same rate and term, more than the 75% loan, so loan-to-value is the limit here. NOI could fall to $84,058, about 23% or $24,643 lower, before this loan drops to 1.20x. These figures are illustrative.
The sample loan is 75% of price for illustration, not a program cap. For a conventional 2- to 4-unit investment purchase, Fannie Mae and Freddie Mac allow up to 75% loan-to-value, so at least 25% down. If you'll live in one unit of a 2- to 4-unit building, conventional rules can allow much less down. FHA, VA, DSCR and commercial loans use their own rules, and 5+ units usually need a commercial or agency multifamily loan sized on DSCR and loan-to-value. Get current terms from your lender.
Contractor assumptions
Repairs are an annual operating line, not a construction budget. Reserves are $300 per unit a year, a set-aside, not a bid. A building that needs roofs, boilers, or unit turns before it stabilizes needs a capital budget you add to your own sources and uses. Occupancy of 95% and loss-to-lease of 1% are defaults. A building in lease-up is not 95% occupied, so treat the free headline as the stabilized case.
Common pitfalls
The sample loan stays at 75% of the purchase price when you change that price. A different loan amount, rate, or interest-only period is not what the free headlines are using.
Loss-to-lease and occupancy already reduce income on the sample. Typing market rents and then also assuming full collection double-counts the optimistic case.
What stays on the subscription
The subscription opens the unit mix, every expense line, reserves, growth, the exit cap, the five-year IRR, saved deals, and the PDF. The free multifamily calculator keeps ten units in a 6-and-4 mix and a 75% loan. Standard is $9.99 a month after the 48-hour trial. Founding is $5.99 a month for the first 100 subscribers and remains $5.99 while that subscription is active.
Cap rate and cash flow are estimates from these inputs. They are not an appraisal and not a lender's underwriting. Taxes, insurance, and the real loan terms belong in the paid worksheet.
Sources
Fannie Mae, Eligibility Matrix (August 5, 2026), https://singlefamily.fanniemae.com/media/20786/display (accessed November 10, 2026).
Freddie Mac, Maximum LTV, TLTV, and HTLTV ratio requirements for conforming and super conforming mortgages, https://sf.freddiemac.com/general/maximum-ltv-tltv-htltv-ratio-requirements-for-conforming-and-super-conforming-mortgages (accessed November 10, 2026).
Questions
How many units does the free multifamily calculator use?
Ten. Six 1-bedrooms and four 2-bedrooms. You can change the rents, not the counts. The paid calculator edits the unit mix.
What is cost per unit or per door on this page?
Price per unit is one of the free headlines: the purchase price divided by the ten units. For equity per unit, divide the equity headline by ten. Renovation cost per unit is not included, because the repair line is an annual operating cost.
What loan and mortgage payment does it assume?
A loan of 75% of the purchase price at 6.75% for 30 years, on the sample rate and term. On the $900,000 sample loan that is $5,837 a month in principal and interest. Closing cost lines stay at the dollar defaults and do not scale with price.
What is a good DSCR for a multifamily loan?
Lenders set their own minimum, so ask yours. A DSCR of 1.00x means NOI only just covers the loan payments. The sample building is at 1.55x. Cap rate is a different number: year-1 NOI divided by the price, with the loan left out.
Does this include a renovation budget?
No. The repair line is an annual operating expense. For a rough one-time project base, the rehab cost estimator multiplies square feet by a cost per square foot you choose.
Where is the five-year IRR?
In the paid multifamily calculator, with the exit cap and selling costs. The free page stops at year one: cash flow, cap rate, equity, the loan payment, DSCR, and price per unit.