Measure the length of the room in feet
Measure the width of the room in feet
Multiply the length by the width
The result is the square footage
For example, a room that is 10 feet by 12 feet is 120 square feet
For irregular rooms, divide the space into smaller rectangles
Find the square footage of each section
Add the sections together
If measurements are in inches, convert them to feet first by dividing by 12
If the room has closets or alcoves, measure them separately and include them if needed