Gross leasable area (GLA) is the total floor area designed for tenants’ exclusive use and occupancy, the space they lease and pay rent on, including their own basements and mezzanines but excluding shared common areas.
GLA leaves out the corridors, lobbies, shared restrooms, and mechanical rooms that gross floor area (GFA) includes, so on the same building GLA is always the smaller number.
Why retail parking uses GLA
Retail parking demand tracks the space that generates customers, which is leasable floor area. That is why retail parking ratios and demand data are expressed per 1,000 square feet of GLA. The Institute of Transportation Engineers’ Parking Generation manual (5th edition) reports average peak parking demand of 4.58 spaces per 1,000 square feet of GLA for shopping centers, with an 85th percentile of 5.90.
GLA versus GFA in practice
On an illustrative building with 100,000 square feet of GFA and 85,000 square feet of GLA, a ratio of 4 per 1,000 produces 340 spaces on GLA and 400 on GFA. When a study, a lease, and a zoning code use different bases, reconcile them before the parking count is fixed. Mixed-use projects add a second adjustment, shared parking, because uses with different peak hours can draw on the same spaces.
Related terms: Gross Floor Area (GFA), Shared Parking, Parking Minimums