Formula:
D=((8*F*C³*N)/(G*d))*(1+(0.5/C²))
Where,
D = Spring Axial Deflection
F = Axial Force
d = Wire Diameter
N = Number Of Active Coils
G = Modulus of Rigidity
C = Spring Index
Thus the Axial Deflection of Helical Spring calculation can be made easier. Online Physics Calculator.