Primary references on this page:
Fannie Mae Multifamily Guide: property income analysis·
HUD MAP Guide chapter 7: project income, rent rolls, vacancy, and collection lossVacancy loss is the income that evaporates while a unit sits empty — between tenants, during a renovation, or because it simply has not leased. If a $1,500-a-month unit takes two months to fill, that turnover cost you $3,000 of vacancy loss before you count a dollar of make-ready expense. Expressed as a percentage of gross potential rent, it becomes the vacancy rate that underwriting models lean on.
Two habits keep vacancy loss honest. First, budget for it even when you are full: a realistic allowance in your pro forma acknowledges that turnover happens, and a model with zero vacancy is telling you a story. Second, measure it in days, not vibes — days vacant per turnover is a number you can manage down with faster make-ready, earlier renewal conversations, and pre-marketing before move-out.
Calculate vacancy loss from days and a declared rent basis
A unit with a $1,800 monthly rent basis is vacant for 14 days in a 30-day month. Under daily proration, vacancy loss is $1,800 ÷ 30 × 14 = $840. Record the unit, start and end timestamps, calendar convention, rate source, availability policy, and the event that ended vacancy. If the operator uses a full-month convention or excludes a planned down unit, the result differs and must be labeled rather than silently substituted.
The $840 is modeled foregone rent, not a bank withdrawal or an invoice. Make-ready expense, advertising spend, a concession to the incoming resident, unpaid occupied-unit rent, and loss to lease belong in separate lines. Fannie Mae and HUD income frameworks distinguish vacancy and collection effects from the potential-rent starting point; the exact internal calculation still depends on the stated reporting policy.
| Input | Value | Evidence |
|---|---|---|
| Monthly rent basis | $1,800 | Named market, contract, or approved underwriting rate |
| Daily rate | $60 | $1,800 ÷ 30 days |
| Vacant days | 14 | Unit status history and signed lease or occupancy event |
| Vacancy loss | $840 | $60 × 14 days |
Turn downtime into an exception workflow
Break the 14 days into controlled states instead of one vague gap. For example: five days of make-ready, six days ready and marketed, and three days between approval and lease start. Each state has different evidence and a different decision owner. A work order and completion acceptance support make-ready; listing publication and inquiry records support marketing; screening and signed lease records support approval-to-start timing.
| State | Days | Primary evidence | Decision supported |
|---|---|---|---|
| Make-ready | 5 | Move-out condition, work orders, completion acceptance | Scope, vendor, and turn-time review |
| Ready and marketed | 6 | Ready date, listing, inquiries, showing record | Price, channel, and response review |
| Approved to lease start | 3 | Approval, signed lease, agreed start date | Process and start-date review |
| Total vacancy | 14 | Continuous unit-status history | Reconciles to the $840 loss |
Budget, actual, and close boundaries
A vacancy budget is an assumption; actual vacancy loss comes from the closed unit-day population and chosen rate basis. Compare them with a bridge for unit count, days, rate, and classification. Planned renovation may be reported separately from market vacancy, but only under a consistent policy. Do not remove a slow unit from GPR after the fact or shift unpaid occupied rent into vacancy to improve collection results.
Close when every rentable unit-day is accounted for, unit status agrees with leases and work orders, rates are versioned, and concessions and credit loss are separated. Vacancy loss can support turn, marketing, pricing, and staffing questions. It cannot alone determine lawful screening choices, prove demand, measure total turnover cost, or show whether a lower asking rent would have produced a better result.
Related tools & guides
Editorial ownership
Written and maintained by the Aptoria editorial teamEditorial method reviewed July 28, 2026. Aptoria reviews scope, source fit, examples, limitations, links, and publication gates. This record does not claim attorney, CPA, lender, appraiser, or other independent professional sign-off.
Related terms
Investing metrics
Vacancy rate
The share of rental units — or potential rent — that sits empty and uncollected over a period.
Investing metrics
Gross potential rent (GPR)
The maximum rental income a property could produce with every unit occupied at market rent for the full period.
Investing metrics
Effective gross income (EGI)
Effective gross income is the property income expected after vacancy and collection loss, plus eligible other property income, before operating expenses.
Leasing
Tenant turnover
The operational transition between an outgoing tenancy and the next occupancy, including possession, reconciliation, make-ready, and leasing.
Investing metrics
Economic occupancy
The share of supportable scheduled rental revenue actually realized for a defined period, with the numerator, denominator, and deductions stated.
Rent
Rent concession
A temporary discount or perk a landlord offers to attract or keep a tenant, such as a free month or reduced rent.
From definition to done
Aptoria runs the routine work behind these terms — rent, books, and screening — inside limits you set. Starts at $19/mo for up to 5 units.
Join the waitlist