Spring Constant Calculator
Hooke's law force, extension and energy.
Enter your values
Enter the spring constant in N/m.
Enter the extension in m.
Enter the attached mass in kg.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Force
- 30 N
- Stored energy
- 1.8 J
- Extension under mass
- 0.1177 m
- Oscillation period
- 0.688 s
Quick answer
Hooke's law says force is proportional to extension for an ideal spring.
F = kx; E = ½kx²
At a glance
| What it does | Hooke's law force, extension and energy. |
|---|---|
| Category | Science |
| Inputs needed | Spring constant, Extension, Attached mass |
| Main output | Force |
| Formula | F = kx; E = ½kx² |
| Cost | Free — no sign-up, no download |
How to use the Spring Constant Calculator
- 1Enter the spring constant in N/m.
- 2Enter the extension or compression.
- 3Add a mass to see static deflection and period.
Inputs explained
- Spring constant(N/m)
- Enter the spring constant in N/m.
- Extension(m)
- Enter the extension in m.
- Attached mass(kg)
- Enter the attached mass in kg.
Worked example
Using the values the calculator loads with:
Inputs
- Spring constant250 N/m
- Extension0.12 m
- Attached mass3 kg
Results
- Force30 N
- Stored energy1.8 J
- Extension under mass0.1177 m
- Oscillation period0.688 s
Frequently asked questions
Does Hooke's law always hold?
Only below the elastic limit — beyond it the spring deforms permanently.
How do I measure k?
Hang a known mass and divide its weight by the extension.
What do I need to enter into the Spring Constant Calculator?
Just 3 values: spring constant, extension, attached mass. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Spring Constant Calculator work out the answer?
Hooke's law says force is proportional to extension for an ideal spring. It applies the formula F = kx; E = ½kx² and shows the working so you can check each step by hand.
Is the Spring Constant Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.