Measure the length of the room in feet (L)
Measure the width of the room in feet (W)
Multiply length by width: Area = L × W
If the room is a perfect rectangle, use that single calculation
If the room has an irregular shape, split it into rectangles and measure each section’s length and width
Calculate the area of each section: Area_i = L_i × W_i
Add all section areas together: Total Area = Σ(Area_i)
If there are alcoves, bays, or built-in recesses, measure them separately
Subtract recess areas from the main area
For a room with a cut-out/indentation: Total Area = Main Area − Recess Area
For spaces with multiple levels, measure each level separately and add areas only if you need total floor area across levels
Measure in feet, not inches; convert inches to feet by dividing by 12
Round measurements consistently (e.g., to the nearest 0.1 ft) before calculating, or keep full precision and round at the end
Verify by re-measuring at least one side, especially if dimensions differ or seem inconsistent