How to Calculate the Square Footage of a Room

To find the square feet of a room, simply measure the length and width of the room (in feet). Now multiply the length in feet by the width in feet, which will equal the area of the room in square feet. 

For example: A room that is 21' by 17' would equal 357 square feet.

If you have a room that's irregularly shaped, just divide sections of the room into multiple rectangles and calculate the square feet of each area.  Then just add each section together to get the total square footage of the room. 

Note: It's always a good idea to round each measurement up to the nearest foot or half foot.