Short answer: Physical occupancy is the share of your space that is rented: rented units ÷ total units, or rented square feet ÷ total rentable square feet. Economic occupancy is the share of your potential rent you actually collect: rent collected ÷ rent you'd collect if every unit were rented at today's street rate. Track all three. Physical tells you about demand, economic tells you about money.
Occupancy is the number every storage owner, lender and buyer asks about first. But "we're 90% full" can mean three different things, and the gap between them is where most of the money is lost.
The three numbers
1. Unit occupancy
Rented units ÷ total units × 100
Easy to count and easy to explain. It treats a 5×5 locker and a 10×30 drive-up the same, so it can be misleading if your small units are full and your large ones are empty.
2. Square-foot (area) occupancy
Rented square feet ÷ total rentable square feet × 100
This is the number lenders and buyers usually mean, because it reflects how much of your building is producing income. Use rentable square feet (the units themselves), not the gross building area including halls.
3. Economic occupancy
Rent actually collected ÷ gross potential rent × 100
Gross potential rent is what you'd collect in a month if every unit were rented at your current street rate. Economic occupancy captures everything physical occupancy hides: discounts, move-in specials, tenants on old rates, and unpaid rent.
A worked example
A 100-unit site:
| Unit size | Units | Rented | Street rate | Avg. rent paid |
|---|---|---|---|---|
| 5×10 (50 sq ft) | 40 | 38 | $70 | $62 |
| 10×10 (100 sq ft) | 40 | 34 | $120 | $108 |
| 10×20 (200 sq ft) | 20 | 12 | $210 | $200 |
Unit occupancy: (38 + 34 + 12) ÷ 100 = 84%
Square-foot occupancy: rented area = 38×50 + 34×100 + 12×200 = 1,900 + 3,400 + 2,400 = 7,700 sq ft. Total area = 40×50 + 40×100 + 20×200 = 2,000 + 4,000 + 4,000 = 10,000 sq ft. 77%
Gross potential rent: 40×$70 + 40×$120 + 20×$210 = $2,800 + $4,800 + $4,200 = $11,800
Rent billed: 38×$62 + 34×$108 + 12×$200 = $2,356 + $3,672 + $2,400 = $8,428. Say $400 of that went unpaid this month, so collected = $8,028.
Economic occupancy: $8,028 ÷ $11,800 = 68%
So the same site is "84% full", "77% full" and collecting 68% of its potential. The owner who only watches unit occupancy thinks things are fine. The owner who watches all three sees that the large units are the vacancy problem and that discounts and late payments cost about as much as the empty units.
What each number tells you
- Unit occupancy high, area occupancy low: your big units are sitting empty. Look at their price and how they're shown online.
- Physical high, economic low: you're full but under-earning. Check old rates on long-term tenants, discounts that never expire, and delinquency.
- A unit type above about 90%: that size is in demand. It's usually the first place to test a higher street rate. See how to price storage units.
Track it by unit type, monthly
A single facility-wide number hides too much. The most useful view is occupancy by unit type, month by month, next to the street rate for that type. That's enough to make most pricing decisions.
Doing it in a spreadsheet means updating it by hand every month. Management software calculates it continuously. In Unitgrove, the owner dashboard shows unit, area and economic occupancy per unit type.
FAQ
What is a good occupancy rate for self storage?
Many operators and lenders treat a facility in the mid-to-high 80s (percent of area) as stabilized, but what's healthy depends on your market and pricing. A site at 95% may simply be priced too low.
Should I measure occupancy by units or by square feet?
Both. Square-foot occupancy is the standard for valuation and loans. Unit occupancy is useful for spotting which sizes are in demand.
What is the difference between physical and economic occupancy?
Physical occupancy measures how much space is rented. Economic occupancy measures how much of your potential rent you actually collect, so it includes the effect of discounts, below-market rents and unpaid invoices.