Days on market and days vacant measure two different intervals on the same unit, and only one of them maps to lost rent. Days on market runs from the day your ad goes live to the day a lease is signed. Days vacant runs from the last day the old tenancy owes rent to the first day the new one does. A unit can post forty days on market and zero days vacant. Another can post five days on market and fifty days vacant.
Most rent rolls carry one field for this and send one number to the owner. That single number is why two unrelated failures look identical on paper.
Every vacancy has four dates
Before you can measure either clock you need four dates recorded per unit, and they are rarely all in one system.
- Notice date. The day you learn the unit is coming back to you. CMHC treats a unit as available for rent once the existing tenant has given or received notice, even while the unit is still occupied.
- List date. The day the advertisement is live and a renter can reach it. Not the day you wrote it, and not the day the photos came back.
- Signed date. The day both sides have executed the lease. A verbal yes on the phone is not this date.
- Rent start date. The first day the new rent is owed. This is often not the move-in date and not the day keys change hands.
You need one more figure, and it lives somewhere else: the last day the old tenancy owed rent. That sits in the ledger, not in the leasing file.
Days on market is your marketing cycle
Days on market is the signed date minus the list date. It answers one question: once a renter could see this unit, how long did it take to turn that exposure into a signature? Pricing, photos, enquiry handling and showing availability all sit inside this interval. Nothing that happened before the ad went live belongs in it.
That exclusion leaves a gap worth naming on its own. The days between the notice date and the list date are your time to list, and it is the interval most fully under your control. A unit that waited eighteen days on a photographer has eighteen days that neither headline number reports.
Days vacant is the interval that costs money
Days vacant is the count of days the unit carries no rent. If the old tenancy's last paid day is March 31 and the new rent starts May 1, every day in April carries no rent: thirty days vacant. This is the clock that converts to dollars, and it converts with one multiplication.
The multiplication needs a daily rate, and a daily rate is not one agreed figure. Dividing monthly rent by thirty, by the days in that particular month, or by 365 and then by 12 gives three different answers. Pick one rule, write it down, and apply it to every unit, or your lost rent totals will not add up across a portfolio.
Days vacant is also one input to economic vacancy, which widens the question from empty days to every dollar of potential rent that did not arrive.
The two clocks come apart in both directions
Sign a lease while the outgoing tenant is still in place and days on market can run long while days vacant stays at zero. Pre-leasing is how a forty day marketing cycle costs nothing at all. A high days on market figure is not automatically an expense.
Now reverse it. A unit that needs six weeks of work comes off the market, goes back on when the work is finished, and leases in four days. Days on market reads four. Days vacant reads forty six. A manager who reports only the first number shows a clean result straight through the most expensive stretch of the turnover.
Four ways these numbers get reported wrong
- One clock doing two jobs. A single vacancy figure that starts at the notice date and ends at move-in is neither measurement. It cannot be compared to a leasing target or multiplied into a rent loss.
- A start date that resets. Any counter derived from a listing record's creation date starts over when you delete the ad and repost it. If relisting is part of how you refresh a stale vacancy, the original list date has to live in your own records.
- Stopping on move-in. If rent starts April 1 and the tenant takes keys on April 5, the vacancy ended on the first. Measuring to the move-in date adds four days of loss that nobody suffered.
- An unweighted average. Sixty days on a unit asking $2,900 and ten days on a unit asking $1,400 average out to thirty-five days, and thirty-five days converts to no dollar figure. Work out the lost rent per unit, add the dollars, and report the average separately if you want it.
Your vacancy number and the market vacancy rate are different measurements
CMHC counts a unit as vacant in its Rental Market Survey if the unit is physically unoccupied at the time of the survey, and treats it as available for immediate rental when no new lease has been signed and no major renovation is under way. The survey runs during the first two weeks of October, and the published results describe market conditions at that moment.
A market vacancy rate is therefore a share of units at a point in time. Your days vacant is a duration per unit. Neither can be derived from the other, so an owner asking why your vacancy looks worse than the city rate is comparing two unlike things. Compare your days vacant to your own figure from last year instead.
What recording both clocks changes
The two intervals fail for different reasons and they have different owners. Long days on market with short days vacant points at the rent, the listing or the way enquiries get handled. Short days on market with long days vacant points at scheduling: notice handling, trades, inspections and the order of the turnover. A long time to list points at whoever has to approve the ad.
One blended number cannot separate those three, which means it cannot tell you where the next hour should go. Record five dates per unit, derive the intervals from them, and the diagnosis falls out of the arithmetic instead of out of a hunch.