Topic 19.6: Calculating the Number of Lots Available for Development

Learning Objective

After successfully completing this topic, you will be able to calculate the number of lots available for development, given the total number of acres contained in a parcel, the percentage of land reserved for streets and other facilities and the minimum number of square feet per lot.

Building Lot Calculation

This is a basic calculation for developers to estimate how many building sites can be sold in a subdivision. In order to make this calculation, assume the developer shows the following data:
• Total number of acres in the parcel—48 acres.
• The percentage of land that is set aside for streets, parks, and other facilities—28%.
• The minimum number of square feet in a site—8,500.


The answer is that the developer will have approximately 177 building sites available for sale.
• Calculate number of square feet in 48 acres:48 x 43,560 sq. ft. per acre = 2,090,880 sq. ft.
• Calculate the number of square feet taken by roads and parks: 2,090,880 x 28% = 585,446.4.
• Subtract the road and park square footage from the total: 2,090,880 – 585,446.4 = 1,505,443.6 square feet available for sites.
• Calculate the number of sites by dividing square feet available for sites by the minimum lot square footage to get the number of sites: 1,505,443.6 ÷ 8500 = 177.11, or 177 lots.