# Curie Constant Calculator

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

> The Curie constant calculator finds the Curie constant of a paramagnetic material from the number density of magnetic atoms (given directly or from a cubic lattice) and their magnetic moment in Bohr magnetons.

## Inputs

- Number density from
- Number density (m⁻³)
- Lattice constant a (Å, nm, pm)
- Atoms per cubic cell
- Effective moment (Bohr magnetons)

## Results

- Number density
- Curie constant C

## Formula

```
C = μ₀·n·μ² / (3·k_B),  μ = p·μ_B,  n = atoms per cell / a³
```

## Explanation

The Curie constant sets how strongly a paramagnet magnetises at a given temperature. It depends on how many magnetic ions there are per volume and the size of their moments.

### How to use the Curie Constant Calculator

- **Number density from**
- **Number density (m⁻³)**
- **Lattice constant a**
- **Atoms per cubic cell**
- **Effective moment (Bohr magnetons)**

Results update as you type, every field has its own unit menu, and everything is calculated in your browser.

### How it works

Choose how to give the number density and enter the effective magnetic moment.

### Inputs explained

FieldWhat to enterNumber density fromChoose one: Direct value, Cubic latticeNumber density (m⁻³)A numberLattice constant aUnits: Å, nm, pmAtoms per cubic cellChoose one: Simple cubic (1), Body-centred (2), Face-centred (4)Effective moment (Bohr magnetons)A number

### Example values

How the main result changes when **Number density** changes and everything else stays at the example values above:

Number density (m⁻³)Curie constant C (K)5.00e271.42897.50e271.42891.00e281.42891.25e281.42891.50e281.42892.00e281.4289

## Worked example

Inputs — Number density from: Cubic lattice; Lattice constant a: 4 Å; Atoms per cubic cell: Simple cubic (1); Effective moment (Bohr magnetons): 5.92.

Results — Number density = 1.5625e28 m⁻³; **Curie constant C = 1.42891 K**.

## Key terms

- **Bohr magneton**: eħ/(2mₑ).

## FAQ

**What is the effective moment of Mn²⁺?**
About 5.92 μ_B.

**What units does C have here?**
Kelvin (dimensionless susceptibility × K).

**How is C used?**
χ = C/T (Curie law).

**What is a Bohr magneton?**
The natural unit of electron magnetic moment, 9.274 × 10⁻²⁴ J/T.


## Sources

- [OpenStax – University Physics Volume 3](https://openstax.org/details/books/university-physics-volume-3)
- [NIST – Fundamental physical constants](https://physics.nist.gov/cuu/Constants/)