About the area calculator
Area is the amount of flat surface inside a shape, measured in square units. Pick a shape on the tabs, enter its measurements and choose a unit of length. The result is given in square units of the same length unit.
Where it makes sense, the calculator also gives the perimeter or circumference, and converts the area to square meters, square feet, square inches, square centimeters, acres and hectares.
Use the same unit for every measurement. If your length is 5 feet and your width is 60 inches, convert one of them first.
Formula
- Square: s²
- Rectangle: l × w
- Triangle: ½ × base × height
- Circle: π × r²
- Ellipse: π × a × b
- Trapezoid: ½ × (a + b) × h
- Parallelogram: base × height
- Rhombus: ½ × p × q
- Sector: ½ × r² × θ (θ in radians)
- Regular polygon: n × s² ÷ (4 × tan(π ÷ n))
- Ring: π × (R² − r²)
Example
A circle with a radius of 5 m has an area of π × 25 ≈ 78.54 m². A trapezoid with parallel sides 3 and 5 and height 4 has an area of ½ × 8 × 4 = 16.