Area Calculator
Choose a shape, enter its measurements, and get the area along with the formula used. Rectangles, squares and circles also show the perimeter.
Type a number and the answer appears straight away.
Area40 square units
- Formula
- length x width
- Perimeter
- 26
- Diagonal
- 9.43398
The answer is in the square of whatever unit you measured in: feet give square feet, meters give square meters.
The math behind it: Area
rectangle: length x width; triangle: base x height / 2; circle: pi x radius squared
A triangle with a base of 10 and a height of 6 has an area of 30 square units, and a circle with a radius of 5 has an area of 78.54. The answer comes out in the square of whatever unit you measured in.
Common questions
How do I calculate area?
For a rectangle, multiply the length by the width. For a triangle, multiply the base by the height and halve it. For a circle, multiply pi by the radius squared.
How do I find the area of an irregular shape?
Split it into simple shapes such as rectangles and triangles, work out the area of each, and add them together.
What is the difference between area and perimeter?
Area is the space inside a shape, measured in square units. Perimeter is the distance around its edge, measured in ordinary units of length.
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