Each Magic the Gathering Planar Chaos Booster Box contains 15 cards game per pack and 36 packs in display box.
Planar Chaos set features 165 cards, with randomly-inserted premium cards. All cards are tournament legal. The set includes 60 commons, 55 uncommons, and 50 rares. It will be available in booster packs, theme decks, and Fat Packs. Starting with Time Spiral, there has been a change in how premium cards are distributed. Previously, premium cards replaced a card of the same rarity, so a premium rare would replace a standard rare, a premium uncommon would replace a standard uncommon, and a premium common would replace a standard common.
In Time Spiral and in future sets, all rare, uncommon, and common premium cards will replace a standard common instead. It is now possible for there to be two rares in one pack: the standard rare card plus a premium rare (which replaces a standard common).