Odds
Blackjack Odds: The House Edge, Dealer Bust Chances, and How Often You Win
Most blackjack odds you find online are copied from somewhere else. These aren't. We played 12 million rounds of perfect basic strategy through the rules engine that deals every hand at BlackJack Streak, and calculated the dealer's bust chances exactly for a six-deck shoe. Here is what the game really looks like in numbers, and what each number means at the table.
The short version
You lose more rounds than you win, yet the house edge is tiny. The gap is closed by the hands that pay more than even money: blackjacks at 3 to 2, and doubled hands, which win more often than they lose. That's the core of blackjack math, and why playing those hands correctly matters so much.
The house edge, measured
The house edge is the share of your starting bet the game keeps over the long run. At BlackJack Streak's default rules (six decks, dealer stands on soft 17, double after split, late surrender, blackjack pays 3 to 2), perfect basic strategy faces an edge of 0.38%, plus or minus 0.02%. Bet 10,000 chips a hand for 1,000 hands and you'd expect to be down about 38,000, give or take a lot of luck.
Make the dealer hit soft 17 and the edge rises to 0.55%, plus or minus 0.02%. That one rule costs you about 0.17% in our measurement, close to the 0.2% usually quoted.
| Dealer stands on soft 17 | Dealer hits soft 17 | |
|---|---|---|
| Rounds simulated | 40,000,000 | 40,000,000 |
| House edge (per starting bet) | 0.38% ± 0.02% | 0.55% ± 0.02% |
| Rounds won | 42.40% | 42.18% |
| Rounds lost | 49.10% | 49.45% |
| Rounds pushed | 8.49% | 8.38% |
| Rounds where you double | 10.40% | 10.86% |
| Doubled hands that win | 55.11% | 54.91% |
| Rounds where you split | 2.78% | 2.78% |
A round counts as won or lost by its total result, so a split where one hand wins and one loses is a push for the round.
How often you get blackjack
With six decks, the chance of being dealt an ace and a ten-value card as your first two cards is 4.75%, or about once every 21 hands. The dealer gets one just as often. When you both have it, the hand is a push, which is why your paid blackjacks in our simulation came to 4.51% of rounds rather than the full 4.75%.
Every one of those pays 3 to 2 at BlackJack Streak, and that payout is worth a lot. A table that pays blackjack at 6 to 5 instead costs you about 1.4% of every bet, which is four times the whole house edge of a good game. It's the single worst rule change in blackjack.
How often the dealer busts, by upcard
This is the table behind almost every basic strategy decision. It shows how often the dealer ends up over 21 for each upcard, with a six-deck shoe, given that the dealer doesn't have blackjack (the dealer peeks, so a blackjack would already have ended the round).
| Dealer upcard | Bust chance (stands on soft 17) | Bust chance (hits soft 17) |
|---|---|---|
| 2 | 35.4% | 35.7% |
| 3 | 37.4% | 37.7% |
| 4 | 39.6% | 39.8% |
| 5 | 41.8% | 42.0% |
| 6 | 42.3% | 43.9% |
| 7 | 26.2% | 26.2% |
| 8 | 24.4% | 24.4% |
| 9 | 22.9% | 22.9% |
| 10 | 23.0% | 23.0% |
| Ace | 16.7% | 20.1% |
Two things jump out. First, there's a cliff between 6 and 7: the dealer busts about 42% of the time with a 6 showing and only about 26% with a 7. That cliff is why basic strategy tells you to stand on 13 to 16 against a 2 through 6 and hit against 7 or higher. Second, hitting soft 17 mostly changes the 6 and the ace, because those are the upcards most likely to land on soft 17.
Overall, across every upcard, the dealer busts a little under 30% of the time.
Your chance of busting when you hit
The other half of every hit-or-stand decision. These are the chances that one more card takes a hard hand over 21:
| Your hard total | Chance the next card busts you |
|---|---|
| 12 | About 31% |
| 13 | About 38% |
| 14 | About 46% |
| 15 | About 54% |
| 16 | About 62% |
Put the two tables side by side and the strategy writes itself. Hitting 16 busts you 62% of the time, which sounds terrible. But standing on 16 against a dealer 10 only wins when the dealer busts, and that happens about 23% of the time. Bad options both, and hitting is the less bad one. Where surrender is allowed, giving up half the bet beats both.
Frank says
“In the old days, the casino gave you free drinks so you’d forget the odds. Here, we just give you the odds.”
Insurance, by the numbers
When the dealer shows an ace, insurance pays 2 to 1 if the hole card is a ten. To break even, the dealer would need a ten underneath more than a third of the time. From a fresh six-deck shoe, 96 of the remaining 311 cards are tens: about 30.9%. So insurance loses roughly 7% of whatever you put on it. That's why every strategy chart, and Frank at BlackJack Streak, tells you to decline it. The exception is card counting, where you can tell when the shoe has become rich in tens.
What the common rule changes cost you
| Rule | Effect on you |
|---|---|
| Blackjack pays 6 to 5 instead of 3 to 2 | About 1.4% worse |
| Dealer hits soft 17 | About 0.2% worse (0.17% in our simulation) |
| Fewer decks in the shoe | Slightly better for you |
| Late surrender allowed | Slightly better for you |
| Doubling after a split allowed | Slightly better for you |
BlackJack Streak lets you change the deck count (1, 2, 4, 6 or 8), soft 17, and surrender in Settings, so you can see these differences yourself. The default table already has the player-friendly version of every rule in this list except the deck count.
How streaky blackjack really is
Because you lose about 49% of rounds, losing streaks are a normal part of the game, not a sign of a broken shuffle. Counting pushes as streak-breakers, here's how likely a streak is within 100 and 500 rounds of perfect play:
| Streak | Within 100 rounds | Within 500 rounds |
|---|---|---|
| Lose 5 in a row | 78.4% | Almost certain |
| Lose 7 in a row | 28.9% | 83.1% |
| Lose 10 in a row | 3.8% | 18.5% |
| Win 5 in a row | 55.1% | 98.4% |
| Win 7 in a row | 12.7% | 50.9% |
If you've ever lost seven straight and wondered whether the game was rigged, now you know: it happens in almost a third of 100-round sessions. BlackJack Streak even has a badge for it, Comeback Kid, earned by winning a round right after losing five in a row. Our article on whether online blackjack is rigged covers how to tell the difference between bad luck and a bad game.
How we made these numbers
We didn't borrow these figures. Here is exactly how they were produced, so you can judge them:
- The engine. Every round was played through BlackJack Streak's own rules engine, the same code that deals and settles every hand on the site.
- The shoe. Six decks, shuffled with the game's cryptographic shuffle and reshuffled when the cut card came out at 75% of the shoe, just like at the table.
- The player. One seat, a flat bet every round, perfect basic strategy for the rules in play, and insurance and even money always declined.
- The size. 40 million rounds with the dealer standing on soft 17, and 40 million with the dealer hitting it. The ± figures are one standard error. Across every standard-rules run we've made, 98 million rounds in all, the edge comes out at the same 0.38%.
- The dealer bust table. Calculated exactly for a full six-deck shoe with only the upcard removed, given no dealer blackjack. Our simulation agreed with it to within a few tenths of a percent.
- The streak table. Worked out exactly from the simulated win, loss and push rates.
The house edge is measured per starting bet. Doubles and splits put more chips on the table, so the edge per chip wagered is a little lower still.
What the odds mean for you
Blackjack is one of the closest games a casino offers, but only if you play it well and only at good rules. Over a long session, the edge wins; over a short one, luck swamps everything. The healthiest way to enjoy the numbers is with chips that cost nothing. At BlackJack Streak you start with 500,000 free play chips, the shoe's fingerprint is published before every shuffle, and there's nothing to buy, ever. If you're still learning, our beginner tips turn these numbers into habits.
Questions people ask
What is the house edge in blackjack?
With perfect basic strategy at good rules it is under half a percent. At BlackJack Streak's default six-deck rules we measured 0.38% over 98 million simulated rounds, rising to 0.55% when the dealer hits soft 17.
What are the odds of winning a hand of blackjack?
With perfect basic strategy you win about 42% of rounds, lose about 49%, and push about 8.5%. Blackjacks paying 3 to 2 and well-chosen doubles make up most of the difference.
What are the odds of getting blackjack?
About 4.75% with a six-deck shoe, or roughly once every 21 hands. The dealer gets blackjack just as often, and when you both have one the hand is a push.
Which dealer upcard busts the most?
The 6. With six decks and the dealer standing on soft 17, the dealer busts about 42.3% of the time with a 6 showing, and 43.9% if the dealer hits soft 17. The ace busts least, about 16.7%.
Is it true that losing streaks are normal in blackjack?
Yes. With perfect play, there is about a 78% chance of losing at least five rounds in a row somewhere in 100 rounds, and about a 29% chance of losing seven in a row. Those figures come from BlackJack Streak's simulated win, loss and push rates.