Area Calculator
Find rectangle, triangle or trapezoid area using consistent length units.
Your result
MATHEnter your values and select calculate.
On this page How it works & practical examples
How to use the Area Calculator
Select the shape first and enter matching length units. A rectangle uses two perpendicular side lengths. A triangle uses a base and its perpendicular height, not an arbitrary second side. A trapezoid uses the lengths of its two parallel bases and the perpendicular separation between them. The output is in the square of your chosen length unit.
The calculation
Worked example
A 5-by-4 rectangle has area 20 square units. A triangle with base 5 and perpendicular height 4 has area 10 square units.
Assumptions and limits
Only the displayed shape model is supported. Side lengths alone may not determine the area of a general irregular figure. Enter positive dimensions; measurement uncertainty and curved or uneven boundaries are not accounted for. A large number of decimal places in the result does not imply that the measurements were equally precise.
Common questions
Can I mix feet and meters?
No. Convert all lengths to one unit before multiplying them.
What is a triangle’s height?
It is the perpendicular distance from the chosen base line to the opposite vertex. It is not generally another side of the triangle.