Area Calculation Tool
Old Version

Here is a handy little tool you can use to find the area of common shapes.
Choose the shape, enter the lengths, and then click "Calculate Area"

Try the new Area Calculation Tool.

Triangle Triangle
Area = ½b × h
b = base
h = vertical height
  Square Square
Area = a2
a = length of side
Rectangle Rectangle
Area = w × h
w = width
h = height
  Parallelogram Parallelogram
Area = b × h
b = base
h = vertical height
Trapezium Trapezoid (US)
Trapezium (UK)
Area = ½(a+b) × h
h = vertical height
  circle Circle
Area = πr2
Circumference = 2πr
r = radius
ellipse Ellipse
Area = πab
  Sector Sector
Area = ½r2θ
r = radius
θ = angle in radians

For Triangles, Squares, etc:  
The base "b" or width "w" is:
The height "h" is:
The length "a" is:
For Circle or Sector:  
The radius "r" is:
The angle "θ" in radians is: