Spring Constant Calculator
Calculate the spring constant (k) using Hooke's Law: k = F/x. Enter force and displacement to find stiffness in N/m.
SPRING CONSTANT
500 N/m
IN lbf/in
2.8551 lbf/in
PE STORED
2.5 J
FORMULA
k = F / x
💡 How to Calculate Spring Constant (Hooke's Law)
What Is the Spring Constant?
The spring constant (k) is a measure of a spring's stiffness. It tells you how much force is required to stretch or compress a spring by a given distance. A higher spring constant means a stiffer spring that is harder to deform.
Car suspension springs typically have k values of 10,000–50,000 N/m to support the vehicle's weight while allowing controlled movement. A Slinky has k ≈ 1 N/m. A stiff industrial spring might exceed 100,000 N/m.
How to Calculate Spring Constant
Spring Constant Formula (Hooke's Law)
Where:
- k = spring constant (N/m)
- F = applied force (N)
- x = displacement from equilibrium (m)
Hooke's Law states that the restoring force of a spring is proportional to its displacement: F = kx. This relationship holds as long as the spring is not stretched beyond its elastic limit.
Worked Example
A force of 50 N stretches a spring by 0.1 m (10 cm):
k = 50 / 0.1 = 500 N/m
Elastic Potential Energy
The spring constant is also used to calculate elastic potential energy: PE = ½kx². A spring with k = 500 N/m compressed by 0.1 m stores PE = ½ × 500 × 0.01 = 2.5 J of energy.