BOMA Load Factor Calculator

Calculate commercial lease rentable area, load factors, and rent (ANSI/BOMA Z65.1)

Lease Parameters

The actual physical space the tenant exclusively occupies.
sq ft
Pro-rata share of lobbies, main electrical, building amenities.
sq ft
Pro-rata share of floor hallways, restrooms, janitorial closets.
sq ft
Also known as Add-On Factor.
%
Quoted rate per rentable square foot per year.
$ /sf/yr

Calculation Results

Load Factor
0.00%
Rentable Area
0 sq ft
Annual Rent
$0.00
Monthly Rent
$0.00

Lease Exhibit Summary

Tenant Usable Area: 0 sq ft

Total Common Area Allocation: 0 sq ft

Load Factor (Add-On): 0%

Total Rentable Area: 0 sq ft

Based on an annual rate of $0.00 / rentable sq ft, the total rent obligations are $0.00 per year, payable as $0.00 per month.

About the BOMA Load Factor / Rentable Area Calculator

Brokers, tenants, asset managers, and lease analysts use a BOMA load factor calculation to compare usable area, rentable area, common-area add-ons, and rent exposure. The worksheet turns square-footage inputs into load factor, add-on factor, rentable square feet, and occupancy cost, making lease proposals easier to audit before negotiations or abstracts are finalized.

How it works

  1. Enter the usable area for the suite, floor, or tenant space.
  2. Add the rentable area or building common-area allocation used in the proposal.
  3. Review the load factor, add-on factor, and rentable square footage.
  4. Enter rent per square foot if you need an annual or monthly rent estimate.
  5. Compare the result with the lease measurement standard named in the deal documents.

Frequently asked questions

What is the difference between usable area and rentable area?

Usable area is the space a tenant can occupy and use directly. Rentable area adds the tenant's share of common areas according to the measurement method in the lease.

How is BOMA load factor calculated?

Load factor is generally rentable area divided by usable area. Some teams express the related add-on factor as the excess rentable area divided by usable area.

Can two buildings have different load factors under BOMA?

Yes. Common areas, floor layout, measurement method, and building type all affect the result. Always compare buildings using the same BOMA standard and lease assumptions.

Is rentable square footage the same as the area I can build out?

No. Rentable square footage is a lease and rent allocation measure. Build-out planning should use field measurements, usable area, code requirements, and the final space plan.

References