The topic of magnetic units and magnetic quantities is vast and complicated. Magnetism as a field of physics has been evolving for a long time in different parts of the world. Therefore, plenty of quantities and different unit systems were employed. These days two of the unit systems are still used – SI units and CGS units (mostly in the US). On the following pages, the main differences and conversions between units will be explained, as well as calculators for unit conversion and calculation of some magnetism-related quantities are present.