Area measurement guide
Square footage calculator for rooms and surfaces
Multiply length by width to find the area of a rectangle. Add separate rectangles for irregular spaces and multiply by quantity for matching areas.
Enter length, width, and the number of matching spaces to calculate square footage and perimeter.
Use the square footage calculatorHow to calculate square footage
Measure length and width in feet, then multiply them. For example, a 12-foot by 10-foot room is 120 square feet. The calculator also returns perimeter, which can help estimate trim, edging, or baseboard length.
Area and perimeter formulas
Area = length × width
Perimeter = 2 × (length + width)
Measure an irregular room
- Sketch the room and divide it into rectangles.
- Measure the length and width of each rectangle.
- Calculate each area separately.
- Add the results for total square footage.
Convert inches to feet
Divide the inch measurement by 12 before using the calculator. For example, 6 inches is 0.5 feet. Measure consistently and do not mix feet and inches in the same entry.