Rentable vs Usable Square Footage: What to Ask Before Comparing Two Floors

Two floors, one rentable figure, different rooms

Picture two floors seen on the same afternoon, each listed at 3,500 rentable square feet, the size a 20-person team plans on. The first is a full floor in a side-core building, where the corridor and restrooms sit inside your own premises. At a 15 percent loss factor it gives you about 2,975 square feet to lay out. The second is part of a floor in a center-core tower, sharing a corridor and restrooms with a neighbor. At 25 percent it gives you about 2,625.

That is 350 square feet of difference with nothing on either listing to show it. Partial floors tend to measure heavier than full ones, but the only number that counts is the one for the floor in front of you.

What each floor costs per usable foot and per desk

The lease bills on the rentable figure, so both floors cost the same on paper. As a worked example, say each asks $70 a square foot per year: both run $245,000 a year. Divide by the usable area and, in this example, the first floor costs about $82 for each usable foot and the second about $93.

Per desk the gap is plainer. Suppose the efficient floor seats 20 and the heavy one seats 17 in the same layout. The same check buys three fewer seats, and the monthly cost per desk climbs from about $1,020 to $1,200. Loss factor converts the percentages into the load factor other markets quote.

Questions for the agent showing the space

The person showing a floor normally works for its owner as the listing agent, so get the answers in writing.

• What is the loss factor on this floor, and which measurement method produced the rentable figure?
• Is this a full floor or a partial one, and which shared corridors or restrooms are counted in my footage?
• Will the landlord fund a test fit, drawn to my headcount and room list, before a letter of intent?
• Does the lease let the landlord remeasure, and would a renewal or expansion use today's figure or a new one?

A test fit is the proof. An architect draws your desks, rooms and phone booths on the real floor, columns and core included, and the seat count that comes back is the denominator for every comparison.

Where a 20-person team sees the gap

At this size the difference between a light and a heavy loss factor is the difference between fitting and not fitting. The live floors on this page suit roughly 20 people, and each shows its rentable area and asking rent. Treat those sizes as the starting figure and put the four questions above to the agent on every one.