Square Footage Calculator

To calculate the square footage of a rectangular room, measure the length and width of the room in feet, then multiply these two numbers together. For example, a room that is 12 feet long and 10 feet wide has 120 square feet (12 × 10 = 120). For irregularly shaped rooms, divide the space into rectangles, calculate each area separately, and add them together.

After calculating the square footage of your space, add 5-10% extra for waste, cuts, and mistakes. For complex patterns like herringbone or diagonal installations, add 15-20% extra. For example, if your room is 120 square feet, you should purchase 126-132 square feet of flooring (adding 5-10%). Always check the manufacturer's recommendations, as some materials may require more overage.

For painting, calculate the square footage of each wall by multiplying its height by its width. Add all wall areas together, then subtract the area of windows and doors (typically 20 sq ft per door and 15 sq ft per window). One gallon of paint typically covers 350-400 square feet, so divide your total square footage by 350 to determine how many gallons you'll need. For textured surfaces or dark walls that need multiple coats, plan for additional paint.

Square feet (sq ft) measures area - the size of a two-dimensional surface. It's used for flooring, paint, roofing, etc. Cubic feet (cu ft) measures volume - the amount of three-dimensional space. It's used for calculating soil, mulch, concrete, or other materials where depth is important. To convert from square feet to cubic feet, multiply the square footage by the depth in feet. For example, if you need 2 inches (0.167 feet) of mulch for a 100 sq ft garden, you'll need 16.7 cubic feet of mulch (100 × 0.167 = 16.7).

This calculator provides highly accurate results based on the measurements you enter. However, the final accuracy depends on the precision of your measurements. For best results, measure each dimension twice and use a proper measuring tool. Remember that real-world spaces may have irregularities that affect the actual square footage. For critical applications like purchasing expensive materials or professional construction, consider having measurements verified by a professional.