Every rental property loses some income to vacancy. Units sit empty between tenants, lease-ups take longer than expected, and turnover creates gaps in revenue that add up faster than most owners realize. That lost income has a name: vacancy loss.
Vacancy loss is one of the first deductions applied to gross potential rent in any real estate underwriting model, and one of the most consequential. Underestimate it and your projected NOI is overstated from line one. Overestimate it and you might pass on a deal that was actually worth pursuing.
Understanding what vacancy loss is, how to calculate it accurately, and what's driving it on any given property is a fundamental part of both underwriting new acquisitions and managing existing ones. This guide covers all of it.
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What Is Vacancy Loss?
Vacancy loss is the income a rental property fails to generate because one or more units or spaces are unoccupied during a given period. It represents the gap between what a fully occupied property could collect at market rents and what it actually collects when some portion of the rentable space sits empty.
In real estate underwriting, vacancy loss is expressed as a percentage of gross potential rent and is one of the first deductions applied to arrive at effective gross income. If a property has a GPR of $500,000 and a 5% vacancy loss rate, it loses $25,000 in potential income to vacancy, leaving $475,000 before any other deductions are applied.
Vacancy loss applies across all income-producing real estate types. In residential real estate it reflects empty apartment units or single-family rentals between tenants. In commercial real estate it reflects unoccupied office suites, retail spaces, or industrial units. The calculation is the same regardless of property type, though what's considered an acceptable vacancy loss rate varies significantly by asset class and market.
It's important to distinguish vacancy loss from credit loss, which is income lost to non-payment rather than non-occupancy. A unit that is occupied but not paying rent contributes to credit loss, not vacancy loss. Both are deducted from GPR to arrive at EGI, but they represent different operational problems with different causes and different solutions. Vacancy loss is a leasing problem. Credit loss is a collections problem.
How to Calculate Vacancy Loss: The Formula
The vacancy loss formula is: Vacancy Loss = Gross Potential Rent × Vacancy Rate
Or expressed as a dollar amount: Vacancy Loss ($) = GPR × (Vacant Units ÷ Total Units)
Two numbers. Here's what each one means.
Gross potential rent is the total income the property would generate if every unit were occupied at full market rent for the entire year. As covered earlier in this guide, GPR is the income ceiling of the property before any deductions are applied.
Vacancy rate is the percentage of rentable units or space that is unoccupied during the measurement period. It's calculated by dividing the number of vacant units by the total number of units and multiplying by 100.
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Stabilized Vacancy vs Actual Vacancy
When underwriting a property, there are two vacancy figures worth calculating separately. Actual vacancy is what the property is experiencing right now, based on the current rent roll. Stabilized vacancy is the long-term vacancy rate you expect the property to achieve once it reaches a steady operational state, anchored to submarket data rather than current conditions.
A property that was recently acquired and is mid-renovation may show 20% actual vacancy today but underwrite to a 5% stabilized vacancy once the business plan is executed. Using actual vacancy in a stabilized underwriting model overstates the long-term vacancy loss and understates projected NOI. Using stabilized vacancy assumptions on a property that's currently distressed without accounting for the lease-up period understates near-term vacancy loss and overstates early cash flow. Both figures are useful, but only when you know which one you're looking at and why.
Physical Vacancy Loss vs Economic Vacancy Loss: What's the Difference?
Vacancy loss comes in two forms, and understanding the difference between them is essential for reading a property's revenue performance accurately.
Physical vacancy loss is the income lost strictly from unoccupied units or spaces. It's the straightforward calculation covered in section one: vacant units multiplied by market rent equals physical vacancy loss. It only counts space that has no tenant in it and generates no income whatsoever.
Economic vacancy loss is broader. It captures the full income gap between what a property could collect at full occupancy and market rents and what it actually collects, including not just empty units but also concessions, delinquency, and below-market leases. A unit that is physically occupied but paying $300 below market rent is contributing to economic vacancy loss even though it shows up as occupied in the physical vacancy count.
The formula for economic vacancy loss is:
Economic Vacancy Loss = Gross Potential Rent − Actual Rent Collected
Why the Two Numbers Diverge
Physical and economic vacancy loss diverge whenever occupied units are generating less income than their market rent potential. Here are the three most common reasons:
Concessions reduce the effective rent collected on occupied units. A tenant receiving one month of free rent on a 12-month lease is physically occupying the unit but only paying for 11 months. That one month of lost income is economic vacancy loss even though the unit is never physically empty.
Delinquency creates economic vacancy loss on units that are physically occupied but not paying rent. A tenant who is 60 days behind on a $1,500 per month unit is contributing $3,000 in economic vacancy loss while showing up as occupied in the physical vacancy count.
Below-market leases are the most impactful and most commonly overlooked driver of economic vacancy loss. On value-add acquisitions where tenants are paying rents significantly below current market rates, the gap between in-place rent and market rent represents economic vacancy loss on every occupied unit, not just the empty ones.
Side by Side Comparison: Physical Vacancy Loss vs Economic Vacancy Loss
Which One Matters More
Both matter, but for different reasons. Physical vacancy loss is the more actionable near-term metric because it reflects units that need to be leased. Economic vacancy loss is the more complete revenue metric because it captures everything that's preventing the property from reaching its income potential, not just the empty units.
For underwriting and valuation purposes, economic vacancy loss is the more important number because it directly affects NOI and therefore property value. A property with low physical vacancy but high economic vacancy due to concessions and below-market leases is underperforming its potential just as much as one with high physical vacancy, and the fix requires a different approach.
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Conclusion on Vacancy Loss
Vacancy loss is unavoidable in real estate. Every property will experience some gap between its income potential and what it actually collects. The goal isn't to eliminate vacancy loss entirely. It's to understand what's driving it, benchmark it against realistic market expectations, and manage it down to a level that keeps NOI and property value on track.
Whether you're underwriting an acquisition or managing an existing asset, tracking both physical and economic vacancy loss gives you a complete picture of where income is being left on the table and what it will take to recover it.
Frequently Asked Questions on Vacancy Loss
What Is Vacancy Period Loss?
Vacancy period loss is the rental income lost during the specific time a unit sits empty between one tenant moving out and the next moving in. It covers the make-ready period, the marketing period, and the time required to screen applicants and execute a new lease. On a $1,500 per month unit with a 30-day vacancy period, the vacancy period loss is $1,500.
What Are Vacancy and Collection Losses?
Vacancy and collection loss is a combined line item in real estate underwriting that accounts for two distinct types of income shortfall. Vacancy loss is income lost because units are unoccupied. Collection loss, also called credit loss, is income lost because occupied tenants fail to pay their rent. Together they represent the total deduction applied to gross potential rent to account for real-world revenue shortfalls. Most underwriting models apply a combined vacancy and collection loss rate of 5% to 10% of GPR depending on the property type, market conditions, and tenant quality.
Is a GRM of 12 Good?
A gross rent multiplier of 12 means the property is priced at 12 times its annual gross rental income. Whether that's good depends entirely on the market and property type. In high-cost primary markets a GRM of 12 can represent a reasonable entry point. In secondary or tertiary markets where cap rates are higher and property prices are lower relative to rents, a GRM of 12 may indicate an overpriced asset.
What Vacancy Rate Is Good?
A good vacancy rate for most stabilized multifamily properties is 5% or below, which translates to 95% or higher physical occupancy. For commercial properties like retail and office the acceptable threshold is higher given the longer lease terms and larger income impact of individual tenant departures. A vacancy rate significantly below the submarket average can signal strong management but also warrants scrutiny around whether concessions or below-market leases are masking true vacancy.
