Construction
Square Footage Calculator
Pick a shape and enter your measurements in feet to get the exact square footage, with conversions to square yards and square meters and an optional cost estimate at your price per square foot.
Quick answer: Square footage = length × width in feet. A 12 × 15 ft room is 180 sq ft; a circle is π × (diameter ÷ 2)²; a triangle is base × height ÷ 2. For irregular rooms, split the space into rectangles and add them.
- Square yards13.3
- Square meters11.1
- Acres0.0028
For an L-shaped or irregular room, split it into rectangles, run each one through the calculator, and add the results together.
How it works
1. Measure in feet
Measure the room's length and width in feet at floor level (or the diameter for a circle, base and height for a triangle). Measure to the nearest inch and convert: 6 inches is 0.5 feet.
2. Apply the shape's formula
Rectangles are length × width, circles are π × radius², triangles are base × height ÷ 2. The calculator converts the result to square yards (÷ 9) and square meters too.
3. Handle irregular rooms
L-shapes and rooms with alcoves aren't one formula — split them into rectangles, calculate each, and add the areas. Enter a price per square foot to turn any area into a material or job cost.
Frequently asked questions
How do I calculate the square footage of a room?
Multiply the length by the width in feet. A 12 ft × 15 ft bedroom is 180 square feet. For an L-shaped room, split it into two rectangles, calculate each, and add them together.
How many square feet are in a 12×12 room?
144 square feet (12 × 12). That's 16 square yards of carpet or about 13.4 square meters — a common size, which is why 12×12 is a standard reference for flooring prices.
Do I include closets and hallways?
For flooring and paint, include every surface being covered. For real-estate listings, finished livable area generally counts closets and hallways but excludes garages, unfinished basements, and outdoor spaces.