How to use this square footage calculator
- Shape, choose rectangle, square, circle or triangle to match the space you are measuring.
- Unit, pick feet or metres, the dimension labels switch to match.
- Dimensions, type the measurements the shape needs, length and width for a rectangle, a single side for a square, radius for a circle, base and height for a triangle.
- Price per unit area (optional), add a rate to get a quick material or flooring cost.
- Read the area in square feet, square metres and square yards, the figures update instantly as you type.
Nothing is submitted or stored: the numbers never leave your device, so you can measure rooms, gardens, walls and plots privately.
How to calculate square footage
Area depends on the shape. The four most common ones cover almost every room, plot and surface you are likely to measure:
- Rectangle: area = length × width. A space 12 ft long and 10 ft wide is 120 sq ft.
- Square: area = side × side. A 10 ft square is 100 sq ft.
- Circle: area = π × radius². A circle with a 5 ft radius is about 78.54 sq ft.
- Triangle: area = ½ × base × height. A triangle with a 10 ft base and 8 ft height is 40 sq ft.
Once you have the area in one system you can convert it. 1 square metre = 10.764 square feet, so multiply square metres by 10.764 to get square feet, or divide square feet by 10.764 to go the other way. To reach square yards, divide square feet by 9, since a yard is three feet and 3 × 3 = 9. This calculator does all of that for you, whichever unit you start from.
Estimating cost from area
If you know the price per unit of area, such as a flooring, turf, paint or tiling rate, multiply it by the area to estimate the material cost. Enter a price per unit area and the calculator multiplies it by the area in the unit you selected, so a feet measurement uses cost per square foot and a metres measurement uses cost per square metre. It is a quick guide for budgeting, real quotes may add waste, offcuts and labour on top.
Frequently asked questions
How do I calculate square footage?
For a rectangle, multiply length by width in feet. A 12 ft by 10 ft room is 120 sq ft. For other shapes use side² for a square, π × radius² for a circle, and ½ × base × height for a triangle.
How do I convert square metres to square feet?
Multiply square metres by 10.764. To go back, divide square feet by 10.764. So 10 sq m is about 107.64 sq ft.
How many square feet are in a square yard?
There are 9 square feet in a square yard. Divide your square footage by 9 to get square yards.
How do I estimate cost from square footage?
Multiply the area by the price per unit of area. At 3.50 per sq ft, a 120 sq ft room is about 420 for materials. Add a price in the tool to see the total live.
Is my data uploaded?
No, everything is calculated on your device and nothing is sent anywhere.