Quick answer
Vacancy rate = vacant units ÷ total units × 100. Three empty units out of 40 is a 7.5% vacancy rate.
Enter the vacant units and total units. The calculator returns the vacancy rate.
Related tools: Cap Rate Calculator: Capitalization rate of an income property. Rental Property Calculator: Cash flow, cap rate and cash-on-cash return of a rental. Cash on Cash Return Calculator: Annual pre-tax cash flow relative to the cash you invested.
How to use the Vacancy Rate Calculator
- Enter vacant units (a whole number, 0 or more).
- Enter total units (a whole number, 1 or more).
- Optionally, enter rent per unit (per month) ($) (0 or more).
- Press Calculate to see the result, and use Reset to start again.
| Input | What to enter | Allowed values |
|---|---|---|
| Vacant units | A whole number | ≥ 0 |
| Total units | A whole number | ≥ 1 |
| Rent per unit (per month) (optional) | A number, in $ | ≥ 0 |
Formula and method
Formula
vacancy rate = vacant units ÷ total units × 100
IEEE-754 double precision; money shown to cents, rates to 4 decimals. Results are estimates, not financial advice.
Lost rent is shown when you enter a monthly rent.
Worked examples
These examples are verified: each one is an automated test case that the live calculator must reproduce exactly.
Example 1
Inputs: Vacant units = 3; Total units = 40.
| Result | Value |
|---|---|
| Vacancy rate | 7.5% |
Example 2
Inputs: Vacant units = 2; Total units = 20; Rent per unit (per month) = 1500.
| Result | Value |
|---|---|
| Vacancy rate | 10% |
| Lost rent per month | $3,000.00 |
The first line is the headline result (vacancy rate). IEEE-754 double precision; money shown to cents, rates to 4 decimals. Results are estimates, not financial advice.
Reading it
A 7.5% vacancy rate means 92.5% of units are occupied. Landlords often assume 5 to 8% vacancy in underwriting. Local market vacancy affects rent levels.
Economic vacancy
Physical vacancy counts empty units; economic vacancy also counts lost rent from non-payment and concessions, so it can be higher. Vacant units cannot exceed total units.
How the result changes with vacant units
Holding every other input at the first worked example, this table changes only vacant units. It shows how sensitive the answer is to that one value; each row was produced by running this calculator.
| Vacant units | Vacancy rate |
|---|---|
| 2 | 5% |
| 3 | 7.5% |
| 6 | 15% |
| 12 | 30% |
What happens with invalid input
These messages are produced by the calculator itself, so you know what to fix.
- Vacant units: entering "5" shows "Vacant units cannot exceed total units." beside that field and no result.
- Total units: entering "0" shows "Total units must be at least 1." beside that field and no result.
Choosing between the Vacancy Rate Calculator and similar calculators
Each row shows what a related calculator on this site asks for and what it returns, so you can pick the one that matches your question.
| Calculator | You enter | It returns |
|---|---|---|
| [Cap Rate Calculator](/real-estate/cap-rate-calculator/) | net operating income and property value | Cap rate |
| [Rental Property Calculator](/real-estate/rental-property-calculator/) | purchase price, down payment and mortgage rate | Annual cash flow |
| [Cash on Cash Return Calculator](/real-estate/cash-on-cash-return-calculator/) | annual pre-tax cash flow and total cash invested | Cash-on-cash return |
| [House Flipping Profit Calculator](/real-estate/house-flipping-profit-calculator/) | purchase price, renovation cost and holding costs | Profit |
| [Real Estate ROI Calculator](/real-estate/real-estate-roi-calculator/) | purchase price, sale price and net income during ownership | ROI |
Background: rental property metrics
Rental property metrics answer different questions. The cap rate is net operating income divided by the purchase price and ignores financing; cash flow is income minus operating expenses minus debt service; cash-on-cash return divides annual cash flow by the cash you actually invested. Rules of thumb such as the 1% rule (monthly rent at least 1% of the price) are quick screens, not decisions.
Check the assumptions behind any result: vacancy, management fees, repairs and taxes. Published benchmark ranges for a good cap rate or return vary between sources.
Assumptions and limitations
- Vacant units cannot exceed total units
Estimates only. Taxes, fees and lender or authority rules vary by place and date, so confirm figures with the relevant authority or professional.
If a required value is empty, not a number, or outside its allowed range, the form marks that field with a message and shows no result instead of a misleading number. The automated checks deliberately try invalid entries for vacant units and total units to confirm this.
Frequently asked questions
What is a healthy vacancy rate?
Around 5% is common.
How does vacancy affect income?
Income falls in proportion.
How do I lower vacancy?
Keep rents competitive and respond quickly.
What does the Vacancy Rate Calculator calculate?
Share of rental units that are vacant, with optional lost rent. It returns Vacancy rate.
What formula does the Vacancy Rate Calculator use?
vacancy rate = vacant units ÷ total units × 100. Lost rent is shown when you enter a monthly rent.
What do I need to enter in the vacancy Rate Calculator?
You enter Vacant units and Total units. Optional: Rent per unit (per month) ($).
How is the result rounded or limited?
IEEE-754 double precision; money shown to cents, rates to 4 decimals. Results are estimates, not financial advice. Vacant units cannot exceed total units.
What is an example of a vacancy Rate result?
With vacant units 3 and total units 40, the vacancy rate is 7.5%.
Can I rely on this calculator for a decision?
Estimates only. Taxes, fees and lender or authority rules vary by place and date, so confirm figures with the relevant authority or professional. For this calculator in particular: Vacant units cannot exceed total units.
Related calculators
- Cap Rate Calculator — Capitalization rate of an income property.
- Rental Property Calculator — Cash flow, cap rate and cash-on-cash return of a rental.
- Cash on Cash Return Calculator — Annual pre-tax cash flow relative to the cash you invested.
- House Flipping Profit Calculator — Profit and return on cost of a renovate-and-sell project.
- Real Estate ROI Calculator — Total return on a property from sale gain and net income.
- Rental Yield Calculator — Gross and net rental yield on a property.
Sources
- Standard time-value-of-money relations (e.g. Brealey, Myers & Allen, Principles of Corporate Finance)
Content last reviewed 2026-11-04. Formulas and worked examples are checked by automated tests against independently computed values.