Blackjack rules that change the odds
Blackjack is the one casino game where the rules printed on the table matter as much as the way you play. Two tables side by side can cost very different amounts to play.
Last updated 21 September 2026 · Adults onlyThe aim
Each player plays against the dealer, trying to finish closer to 21 without going over. Cards two to ten count at face value, pictures count ten and aces count one or eleven. A two-card 21—an ace and a ten-value card—is a blackjack.
Basic strategy
For every combination of your hand and the dealer’s visible card, there is a mathematically best decision: hit, stand, double, split or surrender. Published basic-strategy charts show it. A player following one faces a house edge of roughly half a percent under good rules; guessing typically costs several times more.
3:2 or 6:5
The single most important rule. A traditional table pays 3 to 2 on a blackjack—$15 on a $10 bet. Many tables now pay 6 to 5, or $12, which adds about 1.4 percentage points to the house edge. The payout is printed on the felt; read it before you sit down.
Soft 17 and other dealer rules
Some tables require the dealer to hit a “soft” 17 (a hand containing an ace counted as eleven), which adds about 0.2 points to the edge. Rules on doubling after a split, re-splitting aces and surrender make smaller differences, but they add up.
Insurance and side bets
When the dealer shows an ace, you will be offered insurance. It is a side bet that the dealer has blackjack, and for a basic-strategy player it carries a high house edge—decline it. Side bets such as pairs or poker-hand combinations are similarly expensive.
Shuffling machines and pace
Continuous shuffling machines do not change the house edge, but they speed the game up, which raises the cost per hour. A slow, full table costs less per hour than a fast one-on-one game at the same stake.
What casinos may refuse
Casinos are private venues and may limit or refuse play, including by players they believe are counting cards. Counting is not illegal in Nevada, but it is not a way to make money for the overwhelming majority of players, and it is not something we recommend.
| Rule | Effect on house edge |
|---|---|
| Blackjack pays 6:5 instead of 3:2 | about +1.4 points |
| Dealer hits soft 17 | about +0.2 points |
| No doubling after splitting | about +0.14 points |
| Late surrender offered | about −0.07 points |
| Taking insurance (multi-deck game) | the side bet itself carries an edge of about 7% |
Approximate values for six- and eight-deck games played with basic strategy.
The house always
has an edge.
Every casino game is designed so that the casino wins over time. If you play, treat it as the price of an evening’s entertainment, with a fixed budget and a fixed finish time. Never chase losses, and step away when it stops being enjoyable. Adults only.
Read our responsible play guidance