GLA, or Gross Lettable Area, refers to the total floor area of a building that is available for lease or rent. This includes all usable space, such as offices, retail stores, and common areas, but excludes areas that are not suitable for occupancy, such as stairwells and mechanical rooms. GLA is an important metric in the real estate industry as it helps determine the potential income and value of a property. It is often used by landlords, tenants, and investors to accurately assess the size and profitability of a space. GLA is also commonly used in property management to calculate rentable space and allocate expenses among tenants. Overall, GLA is a crucial factor in the success and management of commercial real estate properties.