# Magnetic Constant Constant

Use Magnetic Constant in Calcul.io. See what this built-in constant represents, enter it in an editable calculation, and review related values and units.

## magneticConstant

Magnetic constant (vacuum permeability)

Try it yourself:

```calculio
magneticConstant
```

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## Magnetic constant: vacuum permeability

**magneticConstant** is the magnetic constant μ₀, associated with magnetic fields in vacuum and SI electromagnetic relations.

## Use

It appears in field and inductance formulas alongside the [electric constant](https://calcul.io/constants/electricConstant/index.md) and [speed of light](https://calcul.io/constants/speedOfLight/index.md). Keep units with [multiply()](https://calcul.io/function/multiply/index.md) and convert using [to()](https://calcul.io/function/to/index.md).

## Caveat

Use the current defined value and distinguish vacuum relations from material permeability.

[All constants](https://calcul.io/constants/index.md)