Mana

Mana is Magic: The Gathering's resource, used in order to cast spells and activate abilities. The most common mana source is by tapping lands; although there are also spells, creatures and artifacts which can generate mana. Each player has a mana pool which they can draw mana from.

Mana is also closely related to the concept of Colors. Each card exactly determines which color of mana is produced. Similarly, each spell has a certain mana cost with regarding colors.

The colors of mana can be
 * White
 * Blue
 * Black
 * Red
 * Green
 * Colorless (generic and true) /

Converted mana cost
It is determined by converting each colored mana symbol in the spell's cost to 1, then adding the results to the colorless mana cost of the spell.

The cases in which a spell's converted mana cost can ever vary is for spells with in the mana cost. When an object with in the mana cost is on the stack,  equals whatever value was chosen for it when it was put on the stack. In any other location, equals 0.

Another exception are split cards/Aftermath which have a CMC of both parts of the spell.