Vacancy Rate Calculator
The vacancy rate is a quick, telling measure of how a rental property or portfolio is performing. It answers a simple question: of all the units you have, how many are sitting empty right now? A low vacancy rate signals healthy demand and steady income, while a high one is an early warning that rents may be too high, the units may need work, or local demand may be soft. This calculator turns raw counts into that headline percentage in one step. Enter the number of vacant units and the total number of units, and it returns the vacancy rate along with the number of occupied units so you can see both sides of the picture. The method is the standard one used across residential and commercial property: divide the vacant units by the total units and multiply by 100 to express the result as a percentage. Occupied units are simply the total less the vacant count. Because the inputs are plain counts, the same formula works for a small duplex, a forty unit building, or square footage in a commercial space. Every figure here is computed deterministically from the formula shown below, with a worked example that reconciles exactly to the calculator so you can follow each step.
The vacancy rate divides vacant units by total units and multiplies by 100: vacancy rate = vacant units / total units x 100. With 3 vacant units out of 40 total, there are 37 occupied units and a vacancy rate of 7.50%.
Vacancy rate formula
Vacancy rate = Vacant units / Total units x 100
Occupied units = Total units - Vacant units
Vacant units = units empty right now
Total units = all units in the property
The vacancy rate is a percentage, so the division is multiplied by 100. Occupied units are the simple difference between the total and the vacant count, and the two figures together always account for every unit.
Worked example
A forty unit building has 3 units empty between tenants. The owner wants the vacancy rate.
- Occupied units = 40 - 3 = 37
- Vacancy rate = 3 / 40 x 100 = 7.50%
The vacancy rate is 7.50 percent with 37 units occupied. These are the calculator's default inputs, so the result above matches the widget exactly.
Vacant units and the resulting rate
| Vacant units | Occupied units | Vacancy rate |
|---|---|---|
| 1 | 39 | 2.50% |
| 2 | 38 | 5.00% |
| 3 | 37 | 7.50% |
| 4 | 36 | 10.00% |
Based on a total of 40 units. Compare your figure to local market data rather than a fixed target.
Vacancy rate calculator: frequently asked questions
What is the vacancy rate?
The vacancy rate is the share of rental units that are empty, expressed as a percentage. You calculate it by dividing the number of vacant units by the total number of units and multiplying by 100. It is a simple measure of how much of a property or portfolio is sitting unrented at a point in time, and it is the inverse of the occupancy rate.
How do I calculate vacancy rate?
Divide vacant units by total units, then multiply by 100. With 3 vacant units out of 40 total, the calculation is 3 divided by 40, which is 0.075, times 100, giving a vacancy rate of 7.50 percent. The calculator also shows the occupied units, which is total units minus vacant units, here 37.
What is a good vacancy rate?
It depends on the market and property type. A low vacancy rate, often quoted around 5 to 8 percent for healthy rental markets, signals strong demand. Persistently high vacancy can point to overpricing, poor condition or weak local demand. Compare your figure to local market data rather than to a single universal target.
Is vacancy rate the same as the vacancy and credit loss allowance?
They are related but not identical. The physical vacancy rate measures units that are empty. The vacancy and credit loss allowance used in income analysis also includes rent that is owed but not collected. Investors often blend the two into a single percentage applied to potential gross income when projecting effective gross income.
Can I use this for square footage instead of units?
Yes. The same formula works if you enter vacant square footage as vacant units and total leasable square footage as total units. The result is then the vacancy rate by area rather than by unit count, which is common in commercial property where spaces vary in size.
Official sources
- Buying a house, renting and mortgage basics: US Consumer Financial Protection Bureau (CFPB). As at 25 June 2026.
Reviewed by the CalculatorHub team, edited by James Graham, 25 June 2026. See our methodology. This is general information, not financial, tax, legal or investment advice.