How Much Office Space Do I Need?

An office space calculator is useful for a first estimate, but it is only arithmetic. It multiplies your inputs by someone’s assumption. Two companies with the same headcount can need very different offices if one has client meetings, private rooms and files while the other has a mostly remote team with an occasional all-hands.

So do not start with square feet per person. Start with what happens in the office on a real week, then work up to an area. The published numbers you may run into make the point. The US General Services Administration has used a benchmark of 180 usable square feet per person for general office space, and a May 2026 Department of Energy memo describes a federal design standard of no more than 150 usable square feet per person for new space. Those are federal planning rules, measured in usable area. They are not private-market norms or a target for your company.

Check the type of area in any figure you see. A usable square foot and a rentable square foot are different things, and comparing them will throw off your estimate.

1. Project headcount by role across the proposed lease term, not just today. Include open positions, contractors and likely growth or reductions, and write a low and a high case.
2. Measure attendance. Use badge data, desk reservations or a simple count over several normal weeks. Note the average and the peak day.
3. Set your attendance policy. Decide which days you expect people in, because a Tuesday to Thursday team fills up on the same days.
4. Decide who needs dedicated space. List the roles that need private offices or assigned desks, and those that can share.
5. List the rooms. Count conference rooms by size, phone and focus rooms, reception, pantry, IT, storage, wellness and any specialty space.
6. Convert the list to usable area with your architect or space planner, who can apply sizes that suit your building and furniture.
7. Add circulation, the aisles and paths between everything, which a simple room list tends to leave out.
8. Convert usable to rentable area using the load factor of each building you are considering.
9. Test the result on real floor plans, because column spacing, window lines and core shape all affect the fit.

The last step does the most to catch errors. Our guide to test fits and space programming explains how to get one done and what it tells you. Tenant Advisory Group represents tenants and buyers, and we encourage a test fit before you commit to a building, so the decision rests on a plan and not on an estimate.

Hybrid work is the biggest reason older rules of thumb fail. GSA has acknowledged the problem in its own planning. It says its older utilization rate looked at space per person, but did not factor in time, frequency of use, mobility or work styles. Its enhanced approach applies a mobility factor based on telework.

Here is its formula, used here as an illustration only. Hypothetical, for illustration: a company with 40 assigned employees applies GSA’s 180 usable square feet per person and GSA’s mobility factor of 0.60 for an average of two telework days a week. That is 40 x 180 x 0.60, or 4,320 usable square feet. GSA notes this covers general administrative office space and leaves out special space, and that it can be customized with actual occupancy data.

A private company should apply this with care. An average telework figure does not tell you what happens when everybody comes in on the same days. If half the week is empty and the other half is full, you have to size for the full days or change the schedule. GSA also distinguishes between planning a space and measuring occupancy once it is built, and that second part is useful: check how a new office is really being used, and use that data at your next decision.

Before you cut space based on attendance data, also ask how long your current pattern will last. A policy that changes after you sign can leave you short of space or paying for more than you use.

Your lease lasts for years, and your headcount will change. A company with a confident growth plan may be tempted to lease for the size it hopes to reach. That extra space costs money from day one. A company that leases too tightly may need to move sooner than planned, or live with crowding.

You can often handle this with lease terms and not just more square feet:

• Expansion rights or a right of first offer on nearby space.
• Sublease and assignment rights you can actually use if you shrink.
• A termination option if your plans could change.
• A layout with more shared seating, which can absorb some growth without a move.

Getting the size right has real financial value. Brilliant Staffing & Recruiting, a TAG client that downsized when fewer people were coming to the office, wrote:

Once you have a usable area target, you still cannot compare buildings on the asking square footage alone. BOMA’s office standard is designed primarily to calculate rentable area, and the area you pay for includes a share of common space. Two suites quoted at the same rentable size can offer different amounts of usable space.

Ask each building for the measurement method, the usable and rentable areas, and a floor plan. Then compare cost per person and total occupancy cost, not only the rent rate. A smaller, efficient plan can beat a larger space with a lower quoted rate. Our load factor guide walks through the math.

• ✓What is our low and high headcount across the term?
• ✓What are our average and peak attendance, based on real data?
• ✓Which days do people actually come in, and will that policy last?
• ✓Who needs a private office or a dedicated desk?
• ✓How many meetings happen at once, and how large are they?
• ✓Do clients visit, and what do they need to see?
• ✓Do we need secure rooms, records storage, or special power or cooling?
• ✓Has each building given us its measurement method and load factor?
• ✓Have we seen a test fit on the actual floor plan?
• ✓If we are wrong by a meaningful amount, what lease rights would let us adjust?