Within its elastic limit, a spring stretches in proportion to the force applied.
How to use the Hooke’s Law Calculator
- Spring constant (k)
- Extension
- Want to work backwards? Type a value into Spring force and Extension is calculated for you.
Results update as you type, and every field accepts the units shown in its menu.
How it works
Multiply the spring constant by the extension or compression.
Inputs explained
| Field | What to enter |
|---|---|
| Spring constant (k) | In N/m |
| Extension | Units: m, cm, mm, km, in, ft … |
What each result means
- Spring force = [Spring constant (k)] × [Extension]
- Stored energy = 0.5 × [Spring constant (k)] × [Extension]^2
Example values
How the main result changes when Extension changes and everything else stays at the example values above:
| Extension (m) | Spring force (N) |
|---|---|
| 0.05 | 25 |
| 0.075 | 37.5 |
| 0.1 | 50 |
| 0.125 | 62.5 |
| 0.15 | 75 |
| 0.2 | 100 |
Formula
F = k xE = ½ k x²Worked example
Inputs — Spring constant (k): 500 N/m; Extension: 0.1 m.
Results — Spring force = 50 N; Stored energy = 2.5 J.
Frequently asked questions
What is the elastic limit?
The point beyond which the spring is permanently deformed.
How do I find k?
Hang a known weight and divide the force by the extension.
What formula does the Hooke’s Law Calculator use?
F = k x.
Can I work backwards from the result?
Yes. Type the result you want into Spring force and the calculator finds the matching extension.