Fixed costs continue during vacancy — mortgage, taxes, insurance.
Calculation details
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Use this result
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What does this calculator estimate?
Vacancy directly cuts rental income. This tool shows the effect: monthly rent reduced by your vacancy rate, then minus operating costs and fees — the income you actually collect when a unit isn't fully occupied. Enter rent, vacancy %, costs, and fees to see the impact.
- Effective rent = rent × (1 − vacancy%)
- Vacancy is a direct income reduction
- A small vacancy % compounds into real lost income
Why vacancy must be budgeted
Rents aren't collected 100% of the time — turnover, marketing time, and market softness create vacancy. Investors who ignore it overstate income. The calculator turns the vacancy rate into a dollar figure that belongs in every pro forma.
Limitations to watch for
The model uses a flat vacancy rate — real vacancy comes in chunks (a month between tenants, not 5% every month). The rate varies by market and property quality. Concessions (free months, upgrades) are additional costs.
How to use it in practice
Use a realistic vacancy rate (5–10% typical, higher in weak markets). Compare the net against the mortgage to test cash-flow safety. Add concessions and turnover costs to the operating budget.
['Enter the monthly rent.', 'Enter the vacancy rate and operating costs.', 'Read effective income, costs, and net.']
What vacancy costs
Vacancy is the share of time a unit sits empty: one vacant month in a year is 8.3 percent vacancy. The lost rent is the direct cost, and the calculator shows its impact on cash flow and annual income.
Effective gross income
Gross rent minus vacancy allowance is effective gross income: $24,000 gross at 5 percent vacancy is $22,800 effective. Budgeting on gross overstates income — the calculator applies the vacancy allowance before expenses.
A worked example
A $2,000 monthly unit with 6 percent vacancy: $1,440 lost annually. Effective income drops from $24,000 to $22,560. At 10 percent vacancy, the loss is $2,400 — the difference can flip a marginal cash-flow deal. The calculator shows the effect at any rate.
Vacancy reserves
Smart landlords hold a vacancy reserve: a month or two of rent set aside. The calculator's annual-loss figure is the size of the reserve to plan for.
Reducing vacancy
Market-rate pricing, responsive maintenance, and renewal incentives cut turnover. Each month of vacancy saved adds a month of rent — the calculator makes the dollar value of retention explicit.
How this calculator works
Formula
Effective income = rent × (1 − vacancy %). Net = effective income − operating costs. The tool shows what vacancy costs in dollars.
Worked example
$2,000 rent at 5% vacancy: effective income $1,900; minus $1,200 costs = $700 net.
Assumptions to verify
- Vacancy is spread evenly across the year.
- Rent is at market rate.
- Turnover costs are included in operating costs.
Frequently asked questions
How does vacancy affect income?
Effective income = rent × (1 − vacancy): $2,000 at 5% = $1,900.
What is a realistic vacancy rate?
5–10% is common; higher in weak markets, lower in hot ones.
Why must I budget for vacancy?
Because rent isn't collected during turnovers — treating 100% occupancy as income overstates the deal.
How do I reduce vacancy?
Price at market, keep units rent-ready, renew early, and market continuously.
Is a free month a vacancy cost?
Yes — concessions are effectively lost rent; add them to the loss.
Does vacancy affect the cap rate?
Indirectly — higher vacancy lowers NOI, which lowers the cap rate and valuation.
How do lenders treat vacancy?
They underwrite with a vacancy factor (often 5–10%) regardless of current occupancy.
What is vacancy rate?
The share of time a unit is unoccupied — one vacant month is 8.3%.
What is a typical vacancy allowance?
5–8% is a common planning assumption.
How much should I reserve?
One to two months of rent per unit covers typical vacancy gaps.
Cite this tool
BoringToolsKit. “Vacancy Rate Impact Calculator.” boringtoolskit.com/vacancy-rate-impact-calculator/ (reviewed 2026-08-25). Free to reference in articles, syllabi, and answer posts with a link.
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