Area calculator
Work out the area of a flat shape: a rectangle, triangle, circle, semicircle or trapezium.
Uses only the sizes you enter.
Result
The rectangle has an area of 20 square metres, or 215.278 square feet.
square metres
| In square feet | 215.278 sq ft |
|---|---|
| In square yards | 23.92 sq yd |
Show the workings
| Step | Sum | Answer |
|---|---|---|
| Area of the rectangle | 5 m × 4 m | 20 m² |
| One square foot in square metres | (0.9144 ÷ 3 m)² | 0.093 m² |
| Total in square feet | 20 ÷ 0.0929 | 215.278 sq ft |
Where the figures come from
- A yard in metres: 0.914 m per yard. Source: Weights and Measures Act 1985, Schedule 1. Checked 13 November 2026.
- Feet in a yard: 3 feet per yard. Source: Weights and Measures Act 1985, Schedule 1. Checked 13 November 2026.
Area formulas
- Rectangle or square: length × width.
- Triangle: base × height ÷ 2, where the height is measured at right angles to the base.
- Circle: π × radius², where the radius is half the diameter.
- Semicircle: half a circle: π × radius² ÷ 2.
- Trapezium: (top + bottom) ÷ 2 × height, where the top and bottom are the two parallel sides.
For an awkward shape, such as a garden with a curved end, split it into these shapes, work out each, and add them up.