The spring constant of a spring depends on its

The spring constant (k) of a helical spring is determined by its physical dimensions and material properties. According to the standard formula k = (G * d^4) / (8 * n * D^3), the stiffness depends on the shear modulus (G) of the material, the wire diameter (d), the mean coil diameter (D), and the number of active coils (n). The material's shear modulus represents its inherent resistance to deformation. Geometrically, a thicker wire diameter (d) significantly increases the spring constant, while a larger coil diameter (D) or a higher number of active coils (n) decreases it. Since the number of coils is directly related to the spring's length, the spring constant is a result of the combination of wire thickness, diameter, material, and length. Therefore, thickness, diameter, and material are all critical factors.