Damage calculation is the process of calculating the Damage done to Life Points from an attack and determining which monster(s) is to be destroyed (if any). When an Attack Position monster is destroyed, the damage inflicted is the difference of the attacking monster's ATK minus the ATK of the other monster.

When a Defense Position monster is destroyed, no damage is inflicted, unless a card effect allows piercing damage. When a direct attack is performed, the damage inflicted is equal to the current ATK of the attacking monster unless stated on the card like Cyberdark Edge.