Stress is force spread over an area. The same 1 kN load creates a huge stress in a thin wire and a tiny one in a thick bar. Comparing stress with the material’s yield strength tells you whether a part will deform permanently.
How to use the Stress Calculator
- Method
- Force F
- Cross-section area A
- Young’s modulus E
- Initial length L₀
- Change in length ΔL
Results update as you type, every field has its own unit menu, and everything is calculated in your browser.
How it works
Choose the method and enter the values. Use a negative force for compression.
Inputs explained
| Field | What to enter |
|---|---|
| Method | Choose one: Force and area, Young’s modulus and strain |
| Force F | Units: kN, N, lbf, kgf |
| Cross-section area A | Units: mm², cm², m², in² |
| Young’s modulus E | Units: GPa, MPa, Pa, psi, Mpsi |
| Initial length L₀ | Units: m, cm, mm, km, in, ft … |
| Change in length ΔL | Units: mm, cm, m, in, µm |
Example values
How the main result changes when Force F changes and everything else stays at the example values above:
| Force F (kN) | Stress σ (MPa) |
|---|---|
| 5 | 50 |
| 7.5 | 75 |
| 10 | 100 |
| 12.5 | 125 |
| 15 | 150 |
| 20 | 200 |
Formula
σ = F / A = E·ε, ε = ΔL / L₀
Worked example
Inputs — Method: Force and area; Force F: 10 kN; Cross-section area A: 100 mm²; Initial length L₀: 1 m; Change in length ΔL: 0.5 mm.
Results — Strain ε = 0.0005; Stress σ = 100 MPa; Implied Young's modulus = 200 GPa.
Key terms
- Normal stress
- Force per area acting perpendicular to a surface.
Frequently asked questions
What is the unit of stress?
Pascal (N/m²); usually MPa (N/mm²).
Is stress the same as pressure?
They have the same units, but stress acts inside a solid and can be tension, compression or shear.
What is strain?
The relative change in length.
What happens beyond the yield strength?
The material deforms permanently.