Sphere - Radius from Surface Area

The Radius of a Sphere from the Surface Area calculator computes the radius (r) based on the surface area of a sphere (SA). 

INSTRUCTIONS:  Choose units and enter the following:

• (SA) Volume of Sphere.

Sphere Radius (r): The radius is returned in meters.  However, this can be automatically converted to other length units (e.g. feet) via the pull-down menu. 

The Math

The equation for the surface area of a sphere is as follows:

          SA = 4•π•r²

If we solve for the radius (r), we have the formula for the radius of a sphere based on the surface area which is:

            `r = sqrt( (SA) / (4π) )`

where:

• r is the radius of the sphere
• SA is the surface area.

Sphere Calculators

• Sphere Surface Area based radius (r)
• Sphere Surface Area from Volume
• Sphere Volume from Radius
• Sphere Volume from Circumference
• Sphere Volume from Surface Area
• Sphere Volume from Mass and Density
• Sphere Radius from Volume
• Sphere Radius from Surface Area
• Sphere Weight (Mass) from volume and density
• Sphere Density
• Area of Triangle on a Sphere
• Distance between Two Points on a Sphere
• Sphere Cap Surface Area
• Sphere Cap Volume
• Sphere Cap Weight (Mass) 
• Sphere Segment Volume
• Sphere Segment Weight (Mass)
• Sphere Segment Wall Surface Area (without the circular top and bottom ends)
• Sphere Segment Full Surface Area  (with the top and bottom circles, aka ends)
• Volume of Spherical Shell
• Mass of Spherical Shell