How it works
Choose a shape and enter its dimensions. For a circle, the first value is treated as the radius and the second value is ignored.
Standard formula
rectangle: length × width; triangle: base × height / 2; circle: πr²Worked example
A rectangle 10 by 5 has an area of 50 square units. A circle with radius 5 has an area of about 78.54 square units.
Frequently Asked Questions
Which units does it use?
The answer uses squared versions of the units you enter.
What is needed for a triangle?
Enter the base and perpendicular height.
What does the circle width field do?
It is hidden conceptually: only the first value, the radius, is used.
Can I calculate irregular shapes?
Split the shape into simple parts and add their areas.