Free tool

Load factor calculator

Convert between usable and rentable square feet, derive the load factor, and see what a quoted rate actually costs per usable square foot.

Area
sf

The space inside the demised premises

%

Typically 10–20% for multi-tenant office

Rent
$

Annual, per RSF

Result

Usable area
9,200 sf
Common area shareRentable less usable
1,380 sf
Rentable area
10,580 sf
Load factorRentable ÷ usable − 1
15.00%
Annual rent10,580 sf × $28.50
$301,530
Effective rate per usable sf
$32.77

Load factor and add-on factor are sometimes quoted differently. Confirm which measure the lease uses — BOMA standards define several.

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Load factor is a negotiating term, not a physical fact

Although load factor is derived from measured areas, which areas count as common is a matter of measurement standard and negotiation. BOMA publishes several standards, and they do not produce identical numbers for the same building.

That is why the lease should state the measurement standard and the rentable area as an agreed figure rather than leaving it to be recomputed. A rentable area that shifts between the letter of intent and the executed lease is a rent increase in disguise.

Questions

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