User Rating 0.0
Total Usage 1 times
Is this tool helpful?

Your feedback helps us improve.

About

Leasing office space involves more than just multiplying area by price. A critical concept is the difference between Usable Square Footage (USF)—the space your team actually occupies—and Rentable Square Footage (RSF), which includes a share of common areas like lobbies, hallways, and bathrooms. The ratio between these is known as the "Load Factor" or "Add-on Factor."

This estimator serves two purposes: it calculates the total monthly and annual occupancy cost based on RSF, and it provides a reverse-calculation to estimate how much space a company needs based on its headcount and desired density (e.g., Open Plan vs. Private Offices). This helps startups and facility managers budget accurately without underestimating the spatial needs of their workforce.

office calculator commercial rent load factor rentable square footage startup cost

Formulas

The relationship between Rentable and Usable space is defined by the Load Factor:

RSF = USF × (1 + LoadFactor)

To estimate the Space Requirement based on headcount:

RequiredUSF = Employees × Densityper_person

Total Monthly Cost is calculated on the Rentable area:

Costmonth = RSF × Priceannual12

Reference Data

Office Layout StyleAvg. Density (sq ft / person)Description
High Density (Call Center)80 - 100Rows of small desks, minimal common space.
Open Plan (Tech/Creative)100 - 150Shared benches, breakout zones, some privacy booths.
Mixed Layout (Standard)150 - 200Mix of cubicles (60%) and private offices (40%).
Private Offices (Law/Finance)200 - 400Majority enclosed offices, large conference rooms.
Executive Suite400+Large private suites, extensive reception areas.

Frequently Asked Questions

Load factors vary by building type. For a single-tenant floor, it might be 10-15%. For a multi-tenant floor where you share elevators and restrooms, it is typically 15-20%. In high-rise towers with extensive amenities, it can reach 25%.
You always pay rent on the Rentable Square Footage (RSF). However, you plan your desk layout based on Usable Square Footage (USF). This tool helps you bridge that gap.
Modern open-plan offices typically allocate 100-150 sq ft per person (including their share of meeting rooms/kitchens). Traditional offices with cubicles or private rooms need 175-250 sq ft per person.