In this how to video, you will learn how to calculate the polygon area in ArcMap. First, open the program ArcMap. Next, go to the left column and right click it. Select attribute table. From here, go to options and click add field. Type in Area and click double. Next, right click area at the top and select calculate geometry. Next, select area disabled. Exit the windows. Next, click the red icon at the top and select data management tools. From here, select project. At the top drop down menu, select your file. Click the icon next to the output form. Search for your coordinate system and then click okay. Next, right click your file again at the left column. Select open attribute table and select calculate geometry. Select your units and then hit okay. The table will now reveal the polygon area. Source.