Build-out - Calculation Methods

Calculation Methods

Build-out applies land use or zoning assumptions about density to the available land area. The build-out calculation may deduct land due to physical constraints to development (e.g. sensitive natural resources), potential infrastructure dedications (e.g. streets, public open space, or stormwater management structures), and practical design considerations (e.g. lot layout inefficiencies). Existing buildings may reduce the available capacity for new development. Many times these constraints are not known until well after a build-out calculation is performed.

A build-out calculation multiplies the land area by density factors. Residential density is most often expressed as residential dwelling units per acre (DU/ac), but a minimum lot size is also used (especially in zoning). (Note: outside the United States, the metric system usually uses hectares as the area unit of measurement). A floor area ratio (FAR) typically describes non-residential development, based on the ratio of building floor space to land area, both using the same unit of measure. Additional analysis might estimate the number of buildings or building coverage based on the number of dwelling units per building, the number of stories and/or the building size in square feet.