Spring Constant Calculator

Hooke's Law states F = kx: the force to stretch or compress a spring is proportional to the displacement (x). The spring constant (k) measures stiffness. Discovered by Robert Hooke in 1660, it applies within the elastic limit where the spring returns to original length.

The spring constant (k) measures how stiff a spring is, in units of N/m (Newtons per meter). Higher k means stiffer - requires more force per unit displacement. A car spring might be 100,000 N/m, while a Slinky is ~1 N/m.

No, only within the elastic limit. If stretched too far (plastic deformation), the spring permanently deforms and Hooke's Law fails. Each spring has a maximum force/displacement before permanent damage. Beyond this, k is no longer constant.

Series springs (end-to-end): 1/k_total = 1/k₁ + 1/k₂ (softer). Parallel springs (side-by-side): k_total = k₁ + k₂ (stiffer). Series springs stretch more for the same force; parallel springs share the load and are stronger.

Material stiffness (steel vs. plastic), wire diameter (thicker = stiffer), coil diameter (smaller = stiffer), number of coils (more = softer), and free length. The formula is k = Gd⁴/(8D³n), where G is shear modulus, d is wire diameter, D is coil diameter, n is number of coils.

Car suspensions (absorb bumps), weighing scales (measure force), trampolines, mattresses, door closers, watches (balance wheel), shock absorbers, measuring instruments, and mouse buttons. Springs are everywhere!