In blackjack, each player competes only against the dealer. Cards 2 to 10 count at face value, face cards count 10, and an ace counts 1 or 11. A natural blackjack is an ace plus a ten value card as the first two cards, and it usually pays 3 to 2. Rules vary by table: the number of decks, whether the dealer hits or stands on soft 17, and the blackjack payout all change the house edge. Tables paying 6 to 5 instead of 3 to 2 raise the edge by roughly 1.4 percentage points.
Example
A 10 unit bet on a natural blackjack paying 3 to 2 returns 15 units in profit plus the original 10. At 6 to 5 the same hand returns 12 in profit.