Usable vs Gross Square Footage Calculator
Convert between gross, rentable and usable square footage using a loss or load factor, and see the true rent per usable square foot and space per person.
How Much Of Your Space Is Actually Usable?
Enter the gross or rentable area, the loss (common area) percentage, the rent and your headcount. The calculator finds usable area, effective rent per usable square foot and space per person.
Usable vs Gross Square Footage Estimator
Usable area is what you can occupy; the rest is common space you still pay for.
Understanding Square Footage
Key concepts for leases and space planning
Usable Area
Usable = gross (or rentable) × (1 − loss %). It is the space you can actually occupy.
Load Factor
Load factor = gross ÷ usable. A factor of 1.18 means paying for 18% more than you use.
Effective Rent
Annual rent ÷ usable area shows the real price of your usable space.
Space Per Person
Offices often plan 100 to 200 usable sq ft per person depending on layout.
Typical Loss Factors
Common ranges for building types.
| Space Type | Typical Loss | Load Factor | Notes |
|---|---|---|---|
| Multi-tenant office | 12% – 18% | 1.14 – 1.22 | Shared lobbies and corridors |
| Single-floor suite | 8% – 12% | 1.09 – 1.14 | Fewer shared areas |
| Industrial | 3% – 8% | 1.03 – 1.09 | Minimal common space |
| Retail | 5% – 10% | 1.05 – 1.11 | Depends on mall design |
| Home (gross vs net) | 10% – 25% | 1.11 – 1.33 | Walls and structure |
| Rule of Thumb | Pay for rentable | Use usable | Check measurement standard |
Usable vs Gross Calculator FAQ
Answers to common questions about this calculator.
Gross includes all areas such as walls and common spaces, while usable is the space you can occupy for your own use.
The ratio of rentable (or gross) area to usable area. It shows how much common area you are paying for.
Many offices plan 100 to 200 usable sq ft per person, less with hot desking and more with private offices.
Standards such as BOMA vary by country and building type. Ask the landlord which one is used.