Poker-based card games usually use one deck, but games like baccarat and blackjack can have multiple decks. It’s important to know that the number of decks in a card game influences the house edge and the average payout ratio.
We can use Microgaming as an example. Versions of blackjack include Atlantic City Blackjack, European Blackjack, Vegas Downtown Blackjack and Vegas Strip Blackjack. The number of decks ranges from 1 to 8. Even within variants there can be differences – Classic Blackjack can have 1 (single hand version) or 5 (multi hand version) decks. Baccarat has the normal variant that uses 1 deck and High Limit Baccarat with 8.
The house edge (the percentage of every dollar wagered retained by the casino in the long run) increases as the number of decks increases, when other rules stay the same. It’s more beneficial for players to choose games with fewer decks. For example, in Vegas Downtown Blackjack played with 8 decks the house edge is 0.64%, with 2 decks it’s 0.40% and with one deck it’s 0.01%. It’s even more interesting in Vegas Strip Blackjack because with 1 deck the house edge -0.18% (with 8 it’s 0.43%, and with 2 it’s 0.18%), which means that in the long run the casino is actually losing money. House edge increases when players make wrong moves. That’s more common in multi hand games, which are the ones with multiple decks.
In baccarat it’s different because of the types of bets. The Tie bet and the Player bet both increase with 1 deck, compared to 8 decks (from14.36% to 15.75%, and from 1.24% to 1.29% respectively), but in the most beneficial Banker bet the house edge does go down from 1.06% to 1.01%.