The problem with this type of conversion is that it isn't as simple as it sounds as it involves two different units of measurement - mcg a unit of weight and ml is a unit of volume.
To complete a calculation such as this, you need to be able to factor in the density of the substance that you are looking to convert and include that in the formula calculation.
This Weight To Volume Converter has been designed to help convert between weight and volume.
Density is how tightly packed the atoms and molecules in a substance are, measured in kilograms per meter cubed. If you have a lot of mass in a small area, that's high density. If you have little mass spread over a large area, that's low density.
The formula that relates density, mass, and volume is: D=m/v.
To learn about how mass and volume are connected by a special formula, how to calculate volumes of common 3D shapes, and how to convert between different units of mass and volume, see -Study.com_'s Mass and Volume: Formulas, Unit Conversion & Practice Problems.