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 of the room
If the room is not a perfect rectangle, divide it into smaller rectangular sections
Calculate the square footage of each section
Add the square footage of all sections together
If measurements are in inches, convert them to feet first by dividing by 12
If the room has alcoves or closets, measure them separately and include them if needed