These methods for measuring floor area are intended for application to properties containing two or more use components, including, but not limited to, office, retail, industrial, single and multi-unit residential, hospitality, entertainment, civic and institutional buildings, both private and public. They can be applied to both new and existing properties containing single or multiple floors or buildings, and properties that are either owner occupied or leased to single or multiple tenants. They are not intended for application to site improvements other than buildings, and do not address the measurement of spatial volume.