How to use the Square Footage Calculator
- Choose a shape and feet or metres.
- Enter the measurements and how many identical areas you have.
- Add the material price and a waste percentage to see how much to buy and what it costs.
How it works
Area is length times width for a rectangle, π times the radius squared for a circle, and half the base times the height for a triangle. For an L-shaped or irregular room, split it into rectangles, work out each one and add them up.
Buy more than the exact area to allow for cuts and mistakes. About 10% extra is usual for straight layouts and 15% for diagonal or patterned tile. Measurements in inches can be divided by 12 to get feet.
Formula
Rectangle = length × width Circle = π × (diameter ÷ 2)² Triangle = base × height ÷ 2 1 m² = 10.764 sq ft 1 sq yd = 9 sq ft
Example
A 14 × 12 ft room is 168 sq ft (15.6 m²). With 10% waste you need 184.8 sq ft, and at $4.50 per sq ft the flooring costs about $831.60.
Frequently asked questions
How do I measure an L-shaped room?
Split it into two rectangles, measure each, calculate both areas and add them together.
How many square feet is a 12 × 12 room?
144 square feet, or about 13.4 square metres.
How do I convert square feet to square metres?
Divide by 10.764. 200 sq ft is about 18.6 m².
How much flooring should I buy?
Take the area with waste and round up to whole boxes. Keep a spare box for future repairs.
Last reviewed October 20, 2026. Spotted an error? Tell us.