Measure the room length (in feet)
Measure the room width (in feet)
Multiply length × width
Square feet = length (ft) × width (ft)
If the room is not a rectangle, split it into rectangles
Calculate square feet for each section (each section length × width)
Add the square feet totals together
For L-shaped rooms, subtract the missing rectangle area: (total outer rectangle) − (missing inner rectangle)
For rooms with odd angles, break into smaller rectangles and sum the results
If you measure in inches or centimeters, convert to feet first
Inches to feet: inches ÷ 12
Centimeters to feet: centimeters ÷ 30.48
Round the final square feet to the nearest whole number (or your preferred precision)