---
title: "Usable square feet (USF) — Class A Atlas glossary"
description: "The actual interior area a tenant can occupy."
canonical: https://classa.info/glossary/usable-square-feet
pageType: glossary
lastUpdated: 2026-04-01T00:00:00.000Z
license: "CC BY 4.0 with attribution to Class A Atlas (https://classa.info)."
---

> The actual interior area a tenant can occupy.

## TL;DR

- The actual interior area a tenant can occupy.
- USF excludes building common areas and is the figure used for space planning.

# Usable square feet (USF)

*Measurement · US*

## Short definition

The actual interior area a tenant can occupy.

## Full definition

USF excludes building common areas and is the figure used for space planning. A 30,000 RSF floor with a 25% [loss factor](/glossary/loss-factor) delivers 22,500 USF. USF is the right denominator for headcount-[density](/glossary/density) calculations.

## Why this matters for Class A leasing

Usable square feet (USF) is part of the measurement vocabulary that institutional [Class A](/glossary/class-a) occupiers, landlords, and advisers use across US markets. Understanding it correctly affects how you read lease documents, model occupancy economics, and benchmark deal terms across cities. Class A Atlas tracks the US definition alongside the global standard so [cross-border](/topics/cross-border-expansion) occupiers can translate quickly.

## See also

- [Rentable square feet (RSF)](/glossary/rentable-square-feet)
- [Loss factor](/glossary/loss-factor)

## Related guides

- [How to choose a Class A office: a working framework](/guides/how-to-choose-class-a-office)

---

Citation: Source: Class A Atlas (https://classa.info/glossary/usable-square-feet), updated 2026-04-01T00:00:00.000Z.