What vacancy costs over a year, and the rate to put in your numbers

A single vacancy has a price you can add up on the day the unit sits empty, and the vacancy cost calculator does exactly that. This page asks the planning question instead: averaged over the years you own the place, what does vacancy cost you per year, and what percentage belongs on the vacancy line of a cash flow estimate?

The two answers are not the same number, and the difference is where analyses go wrong.

Nothing here is sent anywhere and nothing is stored. The rent, the days empty and the two move-out costs are the same example the vacancy cost calculator uses for a single vacancy; the average stay is the number you add here. A month is counted as 30.44 days.

A vacancy rate only counts the rent that did not come in. The cleaning, the paint, the listing and the leasing fee happen at the same moment and are just as predictable, but they are not vacancy, so a 3% vacancy line quietly leaves them out.

There are two honest ways to fix it. Raise the vacancy line until it carries both, or keep it as the rent you lose and add a separate line for turnover. The Rental Property Analyzer does the second: a vacancy rate, and a leasing and turnover fee as a share of gross rent. Either works. What does not work is a 3% vacancy line and nothing else.

The mortgage payment. It is paid whether or not the unit is occupied, and when it is occupied the rent is what covers it, so counting it as a cost of the vacancy counts the same money twice. The same goes for taxes and insurance. The cost of a vacancy is the rent that did not arrive and what it took to get the next tenant in.

The average stay moves the result more than anything else. Halve it and the yearly cost nearly doubles, because every move-out brings its own empty days and its own turnover bill. If you do not know your own figure yet, the leases you have signed are the place to look; a guess here deserves a wide margin.

Days empty is the other one, and it is the one you control: a unit shown before the old tenant leaves, priced right on day one, loses fewer of them.

The Rental Portfolio Dashboard takes up to ten properties and shows what your total monthly cash flow becomes if any one of them goes empty, one at a time. For a single property, the Rental Property Analyzer carries vacancy and turnover as separate lines and tests them in a downside scenario.