The Area Calculator helps you compute area Circles 
based on some simple measurements and the shape of the area.
INSTRUCTIONS:: To compute the square footage of the area, you must first identify the shape of the area (see diagrams). The common choices are:
- Circular - Hopefully we all know what a circle looks like.
- Elliptical - This is a flattened circle or oval .
- Three Side - This is a triangle
- Four Sides - This is a quadrilateral and includes the simple rectangle, trapezoid and a parallelogram.
- Many Sides - This is a polygon. The formulas work for any number of equal sided shapes with equal angles.
Pick your shape (see the diagrams), and then enter the measurements when you click on the calculator buttons (top right) or on the links in the following list. The calculator will provide the square footage.
- Circular Areas
- CLICK HERE to compute the area of a complete circle.
- CLICK HERE to compute the area of a sector or wedge of a circle.
- CLICK HERE to compute the area of an arc section of a circle.
- CLICK HERE to compute the area of an ellipse. 4 Sided Areas
Polygons 
Triangle and Ellipse
- Three Sided (Triangles)
- Four Sided Areas
- CLICK HERE to compute the area of a rectangle.
- CLICK HERE to compute the area of a parallelogram.
- CLICK HERE to compute the area of a quadrilateral with for sides and a diagonal.
- CLICK HERE to compute the area of a quadrilateral with for sides and the sum of the opposing angles.
- CLICK HERE to compute the area of a trapezoid.
- Many Sides
A Word on Units
The measurements you will enter into the calculators are all lengths and a few angles. The measurements can be in any of a large number of different length units. These units go from very small nano-meters to huge astronomical units like light years. The formulas all work with all the different units, but unless you're a rocket scientist or a micro-biologist, you're probably computing the square footage of an area measured in feet or maybe inches. Beside each input field, you will see a symbol that indicates the default units (e.g. ft for feet). If you click on that symbol, you can choose different units that are comfortable for you.
How Area is Used
The calculator helps you compute the square footage of an area, but when will I need it? One big use of square footage is when you are thinking about buying or selling a house. Square footage is one of the basic metrics used in any listing. Click HERE for a good article on the subject by Margaret Heidenry at Realtor.com. Many jobs, especially Do-It-Yourself jobs, require that you know the square footage of an area before you can intelligently buy supplies. This is common inside the house and office and outside in landscaping. Here are few related calculators that are use square footage in calculating materials needed for jobs.