Calculate the area of rectangles, circles, triangles and trapezoids in square feet, square metres and more.
This area calculator works out the area of common shapes – rectangle, square, circle, triangle or trapezoid (trapezium) – and converts it into square feet, square metres, square yards and acres/hectares. Use it for rooms, gardens, walls, plots of land or any surface, in metric or imperial.
| Shape | Formula |
|---|---|
| Rectangle / square | length × width |
| Circle | π × radius² (radius = diameter ÷ 2) |
| Triangle | ½ × base × height |
| Trapezoid / trapezium | ½ × (side A + side B) × height |
A room 4 m × 3 m = 12 m² (about 129 sq ft). For an L-shaped room, split it into two rectangles, work out each area, then add them together.
Split the space into simple shapes (rectangles, triangles), calculate each area separately, then add them together.
One square metre equals about 10.764 square feet.
An acre is 43,560 square feet, or about 4,047 square metres.
For a rectangle, area = length × width. A triangle is ½ × base × height and a circle is π × radius². For complex spaces, work out each part and add them together.
One square yard equals 9 square feet. To convert square feet to square yards, divide by 9 — the calculator shows both automatically.
