This calculator requires the use of Javascript enabled and capable browsers. This calculator is designed to give all of the mathematical values of a circle and sphere from only one entered data value. Enter any of the four circle values, area, radius, diameter or circumference, click on Calculate and the other three values are returned in full (up to 18 decimal places) and maximum 3 decimal place rounded values. Also, assuming the same radius and diameter for a sphere, the surface area and volume of that sphere are returned. You may click on Clear Values to do another calculation.
The formulas are as follows:
area = PI * (radius) * (radius) or
area = PI * (diameter / 2) * (diameter / 2)
radius = (diameter / 2) or
radius = sqrt(area / PI)
diameter = 2 * radius or

diameter = circumference / PI
circumference = PI * diameter or
circumference = PI * (radius * 2)
sphere surface area = 4 * PI * (radius * radius)
sphere volume = 4/3 * PI * (radius * radius * radius)

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Updated: 7/2/11
