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Cash Flow per Door Calculator
Per-door cash flow is the standard quick-compare metric for small multifamily investors. Calculate cash flow per unit and across the whole portfolio from rent, vacancy, opex, and debt service.
Property
Loan (portfolio level)
Cash flow per door
-$44
monthly
Portfolio monthly cash flow
-$175
Annual portfolio cash flow
-$2,104
Debt service per door
$887
Reading the number
Negative per-door cash flow. This deal is only viable if you're betting on appreciation or significant rent growth.
Per-door cash flow is a quick portfolio comparison metric. Bigger properties typically have more headroom because operating expenses don't scale linearly. Small properties (1–4 units) need higher per-door cash flow targets to be safe.
How to Use
- Enter the number of units (doors) on the property.
- Enter average monthly rent per unit, vacancy, and per-unit operating expenses.
- Enter the loan amount, rate, and term at the portfolio level — the calculator divides debt service per door.
- Compare per-door cash flow to your minimum (commonly $100–$200/door for stabilized small multifamily).
Frequently Asked Questions
What's a healthy cash-flow-per-door number?
$100–$200/door is a common minimum for small multifamily after vacancy, opex, and debt service. Bigger properties (10+ units) often accept lower per-door because aggregated cash flow still works. Single-family rentals typically need $200+ per door for safety.
Why do investors compare per-door instead of total?
It normalizes properties of different sizes. A 4-plex generating $800/mo and a 12-plex generating $1,800/mo aren't equivalent — but per-door ($200 vs $150) shows the smaller property is more efficient.
Should capex be in operating expenses?
If you want a true cash flow figure, yes — set aside a capex reserve in opex per door. Otherwise a single roof or HVAC replacement can erase a year of cash flow on a small property.
Does this work for short-term rentals?
Yes for portfolio-style operators (multiple units), but the inputs change: variable nightly rent and higher opex (cleaning, supplies, OTA fees, dynamic pricing tools). For STRs, use ADR × occupancy in place of monthly rent × (1 − vacancy).
Related Calculators
Rental Cash Flow Calculator
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Cash on Cash Return Calculator
Convert per-door cash flow into a return on the cash invested.
Cap Rate Calculator
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DSCR Calculator
Make sure the loan still passes the lender's DSCR floor.
Break-Even Occupancy Calculator
Find the occupancy floor below which per-door cash flow goes negative.
Rent Roll Calculator
Build the unit-by-unit rent roll that drives per-door averages.
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