By ToolzHive
About this tool
Calculate the area of rectangles, circles, triangles, trapezoids and more shapes.
How to use Area Calculator
- Choose the shape and unit.
- Enter the measurements shown for that shape.
- Read the area, perimeter and the area in other units.
Worked example
A 3-4-5 triangle entered with three sides has an area of 6 square units, calculated with Heron’s formula.
What is Heron’s formula?
It finds a triangle’s area from its three sides: √(s(s − a)(s − b)(s − c)), where s is half the perimeter.
Why are the units squared?
Area is measured in square units, such as m² or ft².
Put this guide into practice
- Area Calculator — Calculate the area of rectangles, circles, triangles, trapezoids and more shapes.