# formatDiameter

> Formats a diameter value in millimetres to the active diameter unit string, rounded (never raw floating-point) and using the target locale's decimal separator.

> **formatDiameter**(`mm`, `units`, `locale`): `string`

Formats a diameter value in millimetres to the active diameter unit
string, rounded (never raw floating-point) and using the target locale's
decimal separator.

## Parameters

### mm

`number`

### units

`DiameterUnits`

### locale

`"en"` \| `"pt"`

## Returns

`string`