Key points
- Blackjack is played against the dealer, not other players. The house edge depends on the table rules.
- A natural paying 3:2 instead of 6:5 is the most important rule. On a €10 bet, it is the difference between €15 and €12.
- Dealer hits or stands on soft 17, surrender, doubling and splitting rules also shift the edge.
- Basic strategy reduces the house edge but does not remove it. No betting system creates an advantage.
Blackjack vs poker
In blackjack, each player plays against the dealer. You win by finishing closer to 21 than the dealer without going over. The dealer follows fixed rules. Poker is played against other players, with the house taking a rake. Casino "poker" games against the dealer are different again. See online poker.
The rules that change the house edge
| Rule | Better for the player | Worse for the player |
|---|---|---|
| Payout for a natural (ace plus 10-value card) | 3:2 | 6:5 |
| Dealer on soft 17 | Stands (S17) | Hits (H17) |
| Surrender | Late surrender allowed | No surrender |
| Doubling | On any two cards, and after splits | Only on 9–11 or 10–11 |
| Number of decks | Fewer | More |
Why 6:5 matters: the arithmetic
A natural is dealt about 4.8% of the time from a multi-deck shoe. At 3:2 a natural pays 1.5 times your bet. At 6:5 it pays 1.2 times, which is 0.3 times your bet less. Ignoring pushes against a dealer natural, 4.8% × 0.3 is about 1.4% of every bet. That is the extra house edge from 6:5 alone, more than the whole edge at many 3:2 tables played with basic strategy.
Example: 200 hands at €10 is €2,000 staked. An extra 1.4% edge costs about €28 over those hands on average.
Basic strategy and its limits
Basic strategy is the mathematically best decision for each hand total against each dealer up-card, for a given rule set. It minimises the house edge but does not eliminate it. Card counting depends on deck penetration and is ineffective in online games that reshuffle every hand. It is also unwelcome in casinos. Progressive betting systems, such as doubling after a loss, change how your results vary, not the expected loss.
Live and RNG blackjack
RNG blackjack uses a random number generator, usually with a fresh shuffle each hand. Live blackjack streams a real dealer and shoe. Both follow the rules shown in the game's help screen. Read that screen to see the payout for a natural, the soft-17 rule and the doubling rules before you play. Side bets usually carry a much higher house edge than the main game.
Sources
Limitations: the probability of a natural is approximate and varies slightly with the number of decks. Edge figures are approximations for typical multi-deck rules. Check each table's rules screen.