The Office You’re paying for Is Bigger Than the One You’re Getting

Understanding the load factor and how it affects what you actual

When you sign an office lease, the square footage in the contract isn’t the square footage you move into. There’s a good chance it’s noticeably larger, and that difference is something worth understanding before you sign.

The standard used to measure your space was written by BOMA (Building Owners and Managers Association). It’s a trade organization founded in 1907 that sets the measurement standards used across the commercial real estate industry.

Notice what’s in the name: Building Owners and Managers. There is no “T” for Tenant. That’s not an accident. It’s just what the organization is. This detail becomes more relevant once you understand the standards BOMA sets.

Under the BOMA standard, your rent is based on rentable square footage, which includes not just your actual office space but also a proportionate share of the building’s common areas.

That includes obvious spaces like:

• Lobbies 

• Hallways 

• Restrooms 

• Mechanical rooms 

But it also includes less obvious areas such as:

• Wall thickness (measured from the outside of walls) 

• Elevator shafts and common corridors 

• Shared amenities like conference centers 

• Building features like atriums 

• Outdoor or semi-common areas like patios and rooftop decks 

In other words, you’re paying for more than just the space your team actually occupies.

The space you physically use is called usable square footage. The difference between usable and rentable is known as the load factor.

For example, if your office has 10,000 usable square feet and the building has a 25% load factor, your rentable square footage becomes:

10,000 × 1.25 = 12,500 rentable square feet

That means you’re paying for 2,500 square feet that you don’t directly occupy.

Now put real dollars to it.

Let’s say the rent is $4.00 per square foot per month.
That extra 2,500 square feet costs you:

• $10,000 per month 

• $120,000 per year 

• $600,000 over a 5-year lease

That’s $600,000 spent on space you don’t actually use.

What matters is that load factors vary significantly between buildings.

Two offices could both be listed at 12,500 rentable square feet at the same price, but:

• One might give you 10,000 usable square feet 

• Another might give you only 9,000 

Same deal on paper. Very different reality.

It’s one of those details that rarely gets explained, but it can quietly change the economics of your lease in a meaningful way.

The standard was written without tenants in the room. That doesn’t mean it can’t work in your favor, but only if you know it exists.