Vacancy & Cash Flow Calculator
Last updated June 2026
How to Use This Calculator
Add each unit with its monthly rent and expected vacancy rate. The calculator shows total effective rent, operating expenses, NOI, and cash flow. Use the sensitivity analysis table to see how different vacancy scenarios affect your bottom line and find your break-even vacancy point.
Where to Find Local Vacancy Data
Do not guess vacancy rates. Use real data from these sources to set accurate assumptions for your market:
- Census ACS (American Community Survey): The U.S. Census publishes rental vacancy rates by county and metro area. Search for table B25004 on data.census.gov. This is the most authoritative free source, though the data lags by 1-2 years.
- Local property management companies: Call 2-3 property managers in your target area and ask what vacancy rates they are seeing. They manage hundreds of units and know the real numbers better than any government data set. Most will share this information freely to build a relationship.
- BiggerPockets forums: Search the BiggerPockets forums for your city or zip code. Local investors regularly post their actual vacancy experience. Look for threads with multiple data points, not just one investor's anecdote.
- City and county housing reports: Many municipalities publish annual housing reports with vacancy data, rental trends, and development pipeline information. Check your city's housing authority or planning department website.
- USPS vacancy data: The U.S. Postal Service tracks addresses receiving no mail delivery. HUD publishes this data quarterly at the zip code level. It captures physical vacancy, not just rental vacancy, but it is useful for spotting neighborhood-level trends.
Calculator
Vacancy & Cash Flow Calculator
Model vacancy rates per unit and see impact on cash flow. Multi-unit supported.
Units (2)
Monthly Expenses
Vacancy Sensitivity Analysis
| Vacancy | Eff. Rent | NOI | Cash Flow |
|---|---|---|---|
| 0% | $2,200 | $1,444 | $544 |
| 3% | $2,134 | $1,387 | $487 |
| 5% | $2,090 | $1,348 | $448 |
| 8% | $2,024 | $1,291 | $391 |
| 10% | $1,980 | $1,253 | $353 |
| 15% | $1,870 | $1,157 | $257 |
| 20% | $1,760 | $1,061 | $161 |
Monthly Cash Flow
$422
$5,066/year
Income
6.4% avg
Expenses
Break-Even Vacancy
29%
Cash flow hits $0 at this vacancy rate
Vacancy Rates by Property Type
Single Family
3-5%
Lowest vacancy. Tenants tend to stay longer and treat the property like their own. Turnover is less frequent but more expensive per unit.
Small Multifamily (2-4)
5-8%
Slightly higher vacancy due to more units turning over. Diversified income means one vacancy does not eliminate all cash flow.
Student Housing
8-12%
High turnover with annual lease cycles. Summer vacancy is common. Rents can be higher per bedroom but management is more intensive.
Section 8 / Subsidized
3-5%
Low vacancy because tenants receive housing assistance and are motivated to keep their voucher. Rents are set by local housing authority.
Why Sensitivity Analysis Matters
Most investors analyze a deal at one vacancy rate and call it done. The sensitivity table shows you the full picture. A deal that cash flows $400/month at 5% vacancy might lose $200/month at 15% vacancy. Knowing your break-even vacancy tells you exactly how much cushion you have before the property starts costing you money.
Stress-test every deal at 10-15% vacancy before buying. If the numbers still work at elevated vacancy, the deal has a solid margin of safety. If it only works at 3-5% vacancy, a single bad month or slow turnover could put you underwater.
Multi-unit advantage
How to Minimize Vacancy
- Price slightly below market: A unit priced 3-5% below comparable rentals fills in days instead of weeks. The lost rent from overpricing for one extra month of vacancy exceeds a year of slightly lower rent.
- Screen thoroughly: A bad tenant who stops paying rent or damages the property creates far more vacancy cost than waiting an extra week for a qualified applicant.
- Maintain proactively: Fix small issues before they become reasons to move. Tenants who feel their landlord is responsive are more likely to renew.
- Start marketing early: Begin showing the unit 45-60 days before the current lease expires. Do not wait until the unit is empty.
Vacancy Rates by Market Type
Vacancy rates vary dramatically depending on property class, location, and tenant profile. Use these benchmarks as starting points, then adjust based on your local data.
- A-class urban (3-5%): New or recently renovated properties in prime locations with strong amenities. These attract high-income tenants who sign longer leases and renew at higher rates. Vacancy is low, but so are cap rates — you are paying a premium for stability.
- B-class suburban (5-7%): Solid workforce housing in decent school districts. The largest segment of the rental market. Turnover happens but units re-lease within 2-4 weeks when priced correctly. This is the sweet spot for most buy-and-hold investors.
- C-class (8-12%): Older properties in less desirable areas with lower rents. Higher turnover, more evictions, and longer re-leasing times. The higher gross yields often look attractive on paper but get eaten by vacancy and turnover costs. Budget conservatively.
- Student housing (10-15% effective, seasonal): Leases follow the academic calendar, creating predictable summer vacancy. A unit might be occupied 10 months and empty 2, giving you roughly 17% physical vacancy. Factor in turnover costs every year — students are hard on units. Effective vacancy rates of 10-15% are realistic even in strong college towns.
- Short-term rentals (variable, calculate as occupancy rate): STRs do not have traditional vacancy. Instead, calculate occupancy rate — the percentage of available nights that are booked. A 70% occupancy rate is equivalent to 30% vacancy. Check AirDNA or Mashvisor for market-specific occupancy data. Seasonal markets can swing from 90% occupancy in peak months to 30% in the off-season, so model the full year, not just the best months.
Always stress-test with the worst case
Frequently Asked Questions
What vacancy rate should I use for rental property analysis?
What is break-even vacancy?
How do I reduce vacancy in my rental property?
How much does one month of vacancy actually cost?
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