BOMA Standards: How Commercial Building Area Is Measured

Last updated: September 27, 2026

Start with the area behind the rent quotation

A price per square foot only makes sense when you know which square feet it covers. An office suite advertised as 12,000 rentable square feet does not necessarily provide 12,000 square feet inside the suite. Equally, a gross building area reported for construction or planning may not be the area identified in a lease.

The expense structure is a separate question. Net, gross, and modified gross leases distribute operating costs differently; those labels do not, by themselves, define how space is measured. Read the measurement provisions and the expense provisions together.

Choose the applicable BOMA standard

The current editions relevant to this guide are Office 2024 (ANSI/BOMA Z65.1), Industrial 2025 (Z65.2), Gross Areas 2024 (Z65.3), and Retail 2025 (Z65.5). BOMA also publishes standards for multi-unit residential and mixed-use properties. Check the edition actually incorporated into the lease rather than assuming a newer edition automatically changes an existing agreement. See BOMA's current standards.

Measuring an industrial building

Industrial measurements should address the actual building configuration and the areas serving its use. A warehouse, a covered loading area, and office space within an industrial property raise different measurement questions. The 2019 industrial standard is historical; the 2025 edition is the current reference. Ask the measurer to identify the governing edition and explain the treatment of each area shown in the property schedule.

For an owner-user acquisition, reconcile the marketing brochure, survey, plans, and measurement report. A building's advertised size is useful context, but an acquisition decision also depends on layout, access, loading, and the suitability of the space for the business.

Gross area: leasing and construction serve different purposes

The 2024 Gross Areas standard provides five methods: Leasing, International, Volumetric, Construction, and Energy Star. A gross-area figure should identify its method; a construction figure should not silently replace the lease's agreed area.

For a whole-building lease, ask whether the measurement includes exterior walls, service areas, covered outdoor areas, or other space outside the business's working area. For construction or replacement-cost analysis, identify the quantities required for that purpose. Avoid treating every reported building area as an interchangeable rent denominator.

Measuring an office building: Method A and Method B

The office standard offers Method A and Method B. Method A uses floor and building allocations that can produce different load factors. Method B uses a single building load factor. Both require the applicable standard's detailed treatment of boundaries and space classifications. Ask which method produced the area schedule and apply it consistently when comparing suites. BOMA's Office 2024 overview discusses choosing between the methods.

Do not infer measurement boundaries from a floor plan alone. Walls, vertical penetrations, service spaces, and amenities can require specific treatment. Ask for the measurement report and allocation schedule, and use a qualified measurement professional to resolve discrepancies.

Load factor: a worked example

Assume a suite has 10,000 usable square feet and the agreed rentable-to-usable multiplier is 1.12, equivalent to a 12% add-on.

1. Rentable area: 10,000 × 1.12 = 11,200 square feet.
2. Annual base rent at $30 per rentable square foot: 11,200 × $30 = $336,000.
3. Annual base rent per usable square foot: $336,000 ÷ 10,000 = $33.60.

The additional 1,200 square feet account for $36,000 of annual base rent in this simplified example. Operating expenses, concessions, parking, and other lease charges are separate. A lower multiplier does not automatically make a building better value; compare total occupancy cost and the space's suitability.

For the distinction between a tenant's share and an area's load factor, read our guide to commercial lease floor areas.

What to verify before signing or marketing a property

• Record the measurement standard, edition, method, date, and professional responsible.
• Reconcile the suite's usable/occupant area with its quoted rentable area.
• Confirm what happens if the building or shared areas change.
• Keep the lease exhibit, floor plan, listing, and marketing package consistent.

If the transaction involves land leased separately from improvements, our ground lease guide explains the different ownership and financing questions. When presenting the property, use clear area labels in your materials. Explore CREOP's commercial real estate software and marketing examples.