Calculating Capacitance of a Circular Disk Capacitor based on Radius

The calculator will calculate the capacitance circular disk cylinders based on given values of permittivity of free space, relative permittivity and radius. The capacitance is a storage device of an electrical charge. The capacitance of a circular disk capacitor on a dielectric substrate backed by a ground plane is presented. The capacitance can be calculated based on the radius.
Formula: C=8εoεra
Where, C = Capacitance of Circular, a = Radius, εo = Permittivity of Free Space, εr = Relative Permittivity
Permittivity of Free Space (εo): 
Relative Permittivity (εr): 
Capacitance Circular Disk Cylinders: F