# Stress Calculator

URL: https://speedycalculator.com/calculators/physics/stress/
Last updated: 2026-10-30

> The stress calculator finds the normal stress in a member from force and cross-sectional area, or from Young's modulus and strain, along with the strain from the change in length.

## Inputs

- Method
- Force F (kN, N, lbf, kgf)
- Cross-section area A (mm², cm², m², in²)
- Young's modulus E (GPa, MPa, Pa, psi, Mpsi)
- Initial length L₀ (m, cm, mm, km, in, ft, yd, mi)
- Change in length ΔL (mm, cm, m, in, µm)

## Results

- Strain ε
- Stress σ
- Implied Young's modulus

## Formula

```
σ = F / A = E·ε,  ε = ΔL / L₀
```

## Explanation

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

FieldWhat to enterMethodChoose one: Force and area, Young's modulus and strainForce FUnits: kN, N, lbf, kgfCross-section area AUnits: mm², cm², m², in²Young's modulus EUnits: GPa, MPa, Pa, psi, MpsiInitial length L₀Units: m, cm, mm, km, in, ft …Change in length ΔLUnits: 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)5507.5751010012.51251515020200

## 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.

## FAQ

**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.


## Sources

- [MIT OpenCourseWare – Mechanics of Materials](https://ocw.mit.edu/courses/2-001-mechanics-materials-i-fall-2006/)
- [The Engineering ToolBox](https://www.engineeringtoolbox.com/)