Find the area of any common shape. This free area calculator covers rectangles, squares, circles, triangles, trapezoids, parallelograms and ellipses — just pick a shape and enter the dimensions.
Shape & size
Choose a shape and enter its dimensions. The area is given in square units of whatever unit you use (e.g. cm → cm²).
Area
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Enter the dimensions
Area measures the 2-D space inside a shape. For perimeter of a circle use the circumference calculator; for 3-D space use the volume calculator.
Use this free area calculator to find the area of common shapes — rectangle, square, circle, triangle, trapezoid, parallelogram and ellipse. Pick a shape, enter its dimensions and get the area instantly.
What this area calculator does
An area calculator finds the 2-D space inside a shape. Choose from seven common shapes, enter the right dimensions, and it applies the correct formula — also showing perimeter or circumference where relevant.
Area formulas by shape
Shape
Area formula
Rectangle
width × height
Square
side²
Circle
π × r²
Triangle
½ × base × height
Trapezoid
½ × (a + b) × height
Parallelogram
base × height
Ellipse
π × a × b
For example, a rectangle 10 by 5 has an area of 50, and a circle of radius 5 has an area of about 78.54.
Units and square units
Area is always in square units. If you measure in centimetres, the area is in cm²; in metres, m². Keep all your inputs in the same unit for a correct result.
How to use the area calculator
Select a shape from the dropdown.
Enter its dimensions in the fields shown.
Read the area (plus perimeter where applicable).
Area FAQ
How do I calculate area?
It depends on the shape: rectangle is width × height, circle is π × r², triangle is ½ × base × height. Pick your shape and the calculator applies the right formula.
How do I find the area of a circle?
Multiply π by the radius squared (A = πr²). A circle of radius 5 has an area of about 78.54 square units.
How do I find the area of a triangle?
Multiply the base by the height and divide by two: ½ × base × height. A base of 10 and height of 8 gives an area of 40.
What units is area measured in?
Square units — cm² for centimetres, m² for metres, and so on. Keep all dimensions in the same unit.
What's the difference between area and perimeter?
Area is the space inside a shape; perimeter (or circumference for a circle) is the distance around it. This tool shows perimeter for several shapes too.
Is the area calculator free?
Yes, this area calculator is completely free, needs no sign-up, and gives instant results in your browser.
