Why It Matters
You need to know the rental vacancy rate before you underwrite any buy-and-hold deal. A low vacancy rate signals tight rental supply, faster lease-up times, and landlord pricing power. A high vacancy rate tells you the opposite: too many units competing for too few tenants, which means concessions, longer vacancies between tenants, and downward pressure on rents.
The national long-run average hovers around 6-7%, but that number is almost useless on its own. A 4% vacancy rate in a growing Sun Belt city is healthy. A 4% rate in a shrinking Rust Belt market with declining economic base could still signal trouble ahead. Context always beats the headline figure.
Read vacancy rate alongside the absorption rate — how quickly new units are being leased — and you get a much cleaner read on where the market is headed, not just where it stands today.
At a Glance
- What it measures: Percentage of rental units currently empty and available to rent
- Formula: (Vacant Rental Units / Total Rental Units) × 100
- Healthy range: 3–7% in most stable markets; below 3% = landlord's market, above 8% = tenant's market
- Primary source: U.S. Census Bureau Housing Vacancy Survey (national/metro), CoStar or Yardi (submarket)
- Updated: Census publishes quarterly; submarket data is typically monthly
- What it affects: Rental rates, concession levels, time-to-lease, property values
Rental Vacancy Rate = (Vacant Rental Units / Total Rental Units) × 100
How It Works
The calculation is simple; the interpretation is not. Divide vacant, rent-ready units by total rental units in the area and multiply by 100. A market with 1,200 vacant units out of 20,000 total has a 6% vacancy rate. Simple arithmetic, but what makes it useful is comparing it to historical averages for that specific market — not national benchmarks.
Vacancy rate moves in predictable cycles. When vacancy falls below equilibrium (typically 4–5% for most metros), landlords gain pricing power, raise rents, and slow or eliminate concessions. Developers respond to rising rents by breaking ground on new supply. New supply eventually pushes vacancy back up. If it overshoots — vacancy climbs above 8–9% — landlords offer free months, waive deposits, and compete for tenants. Understanding where a market sits in this cycle is a core part of analyzing its absorption rate.
Submarkets matter more than metro averages. A city-wide vacancy rate of 7% can mask a 3% vacancy rate in a walkable urban core and a 12% rate in a suburban apartment complex built in the 1980s. Always drill down to the submarket — ideally the specific zip code or neighborhood — you're actually buying into. Metro-level vacancy data obscures the specific conditions affecting your property's leasing performance.
Employment drives vacancy. Markets with a diversified employment diversity buffer tenant demand across economic cycles. When major employers contract or leave, vacancy jumps fast. A market heavily dependent on a single industry — manufacturing, energy, government — is far more vulnerable to sudden vacancy spikes than one with layered job sectors. This is why vacancy analysis always pairs with economic base research.
Homeownership rate shapes rental demand. In markets where the homeownership rate is rising sharply, rental demand may be softening as renters transition to ownership. The inverse is equally powerful: when homeownership drops (often driven by affordability pressure or tightened lending), rental demand strengthens and vacancy falls. Neither trend is permanent, but both affect vacancy trajectory over 3–5 year investment horizons.
Real-World Example
Danielle is evaluating two markets for a portfolio of small multifamily properties. Both markets have similar price-to-rent ratios, but the vacancy data tells different stories.
Market A — Phoenix submarket (central):
- Total rental units: 14,800
- Vacant units: 562
- Vacancy rate: 562 / 14,800 × 100 = 3.8%
- Trend: down 0.9% year-over-year
- Absorption rate: new units lease-up in 47 days average
Market B — Memphis submarket (outer ring):
- Total rental units: 9,200
- Vacant units: 828
- Vacancy rate: 828 / 9,200 × 100 = 9.0%
- Trend: flat for 18 months
- Absorption rate: new units lease-up in 112 days average
The Phoenix submarket at 3.8% and falling is firmly in landlord's market territory. Danielle can underwrite conservatively at 5% vacancy and likely perform better. The Memphis outer ring at 9.0% is tenant's market territory — she'd need to underwrite at least 10–12% vacancy and factor in possible concessions (one free month is common in such markets, worth roughly 8% of annual rent).
Same metro-level headline data. Completely different submarket realities. Danielle passes on Market B and focuses her due diligence on Market A.
Pros & Cons
- Fast read on rental market health — One number tells you whether landlords or tenants hold pricing power in a given area
- Pairs cleanly with rent growth data — Low vacancy and rising rents confirm each other; divergence is a warning sign
- Available for free — U.S. Census Bureau publishes national and metro-level data quarterly at no cost
- Tracks cycles reliably — Historical vacancy data reveals where a market sits in its supply/demand cycle
- Granular submarket data exists — CoStar, Yardi, and local apartment associations publish neighborhood-level vacancy for serious investors
- National averages mislead — A 6% national figure masks huge variation across metros, submarkets, and asset classes
- Lags actual conditions — Published vacancy data is often 30–90 days old; real-time conditions may differ
- Doesn't capture concession depth — A market can report low vacancy while landlords are offering 2 months free rent; occupancy and effective vacancy diverge
- Asset class specificity required — Vacancy rates for Class A luxury apartments don't apply to Class C workforce housing in the same zip code
- Self-reported data quality varies — Small landlords rarely report vacancies to any database; surveys capture larger complexes more reliably
Watch Out
Low vacancy doesn't guarantee rent growth. If vacancy is low because rents have already fallen to clear the market, you're buying into a market that has already adjusted downward. Always check the list-to-sale-ratio on the ownership side and rent trend data side-by-side with vacancy to confirm the direction of the market.
Structural vacancy is different from cyclical vacancy. A market with chronically high vacancy due to population loss, weak economic base, or a permanent contraction in the renter pool is not recovering — it's declining. Don't interpret flat vacancy at 10% as stabilization without checking population and job trends over the past decade.
Concession-adjusted vacancy is the real number. If a landlord is offering one month free on a 12-month lease, effective vacancy is understated by roughly 8%. Markets with widespread concessions often report lower official vacancy while actual economic performance is weaker than the headline suggests. Ask property managers what concessions are standard before accepting any vacancy figure at face value.
Ask an Investor
The Takeaway
Rental vacancy rate is the most direct measurement of rental supply-demand balance in any market. Combined with absorption rate data, local employment diversity, and homeownership rate trends, it gives you the context to underwrite realistic occupancy into your pro forma — and to identify which markets offer genuine landlord pricing power versus which require defensive assumptions. Never skip this number in your market research, and never trust a metro-level figure without drilling into the specific submarket you're evaluating.