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Blackjack Odds & Probability

Blackjack has the best odds of any casino table game — but only if you play correctly. With perfect basic strategy, the house edge drops to around 0.5%. Without it, the average player gives up 2–4% through bad decisions. This page covers the real numbers: bust probabilities, dealer bust rates, house edge by playing style, and what card counting actually does to the math.

House edge by playing style

The house edge is the percentage of each bet the casino keeps on average over the long run. In blackjack, how you play has more impact on this number than almost any other casino game.

Playing styleHouse edgeWhat this means
No strategy (gut feel)2–4%Losing $2–4 per $100 bet on average
Basic strategy (memorized)~0.5%Losing about $0.50 per $100 bet
Basic strategy + Hi-Lo counting−0.5 to −1.5%Player advantage — winning $0.50–1.50 per $100 bet long-run

Assumes 6-deck game, dealer stands on soft 17, double after split allowed, late surrender allowed. Rule variations (H17, single deck, no surrender) shift the edge by up to 0.3%.

Win, loss, and push rates

People often think blackjack is close to 50/50. It is close — but the small edges matter across thousands of hands.

42–44%
Player wins
48–49%
Dealer wins
8–9%
Push

Pushes return your bet, so the effective loss rate is lower than the dealer win percentage suggests. The 5–7% gap between dealer wins and player wins is where the house edge lives. Blackjacks (paying 3:2) partially close that gap in the player's favor.

Probability of being dealt a blackjack

A natural blackjack requires an ace and a ten-value card (10, J, Q, K) as your first two cards. In a 6-deck shoe, there are 24 aces and 96 ten-value cards out of 312 total cards.

Probability of a blackjack~4.75%
Frequency~1 in 21 hands
Payout (standard)3:2
Payout (6:5 — avoid these tables)6:5 (+0.4% to house edge)

The 3:2 blackjack payout is worth about 2.3% to the player over the long run. Tables that pay 6:5 instead effectively give that back to the house. Never play 6:5 blackjack — it nearly triples the house edge compared to a 3:2 game with basic strategy.

Probability of busting when you hit

When deciding whether to hit a stiff hand, the bust probability tells you how likely you are to go over 21 on the next card. This is why basic strategy says to stand on hard 13–16 against weak dealer upcards — the risk of busting is too high relative to the chance the dealer busts on their own.

Hard 12
31%
Hard 13
39%
Hard 14
46%
Hard 15
54%
Hard 16
62%
Hard 17
69%
Hard 18
77%
Hard 19
85%
Hard 20
92%

These are single-deck approximations. In a multi-deck shoe the probabilities are nearly identical because the card composition shifts only slightly.

Dealer bust probability by upcard

The dealer must hit until reaching 17 or more, which means certain upcards are much more likely to produce a bust. Cards 4, 5, and 6 are the weakest dealer upcards — this is why basic strategy is more aggressive about doubling and standing against them.

2
35.3%
3
37.6%
4
40.3%
5
42.9%
6
42.1%
7
26.2%
8
23.9%
9
23.3%
10
21.4%
A
11.6%

The sharp drop from dealer 6 to dealer 7 is one of the most important inflection points in blackjack strategy. Against 2–6, standing on stiff hands and letting the dealer bust is often correct. Against 7+, the dealer is unlikely to bust and you must try to improve your hand.

How card counting changes the odds

Card counting does not change the odds of any individual hand. What it does is identify when the remaining shoe is disproportionately rich in high cards (tens and aces), which mathematically favors the player in two ways:

  • Blackjacks:A shoe rich in aces and tens produces more blackjacks for both player and dealer. But the player gets paid 3:2; the dealer just wins even money. More blackjacks in a high-count shoe is directly profitable for the player.
  • Dealer busts:The dealer is forced to hit on hard 16 and below. A ten-rich shoe means the dealer is more likely to bust when hitting those stiff hands. The player can stand and wait.
True countPlayer edgeAction
−2 or lower−1.5% or worseBet minimum
−1−1.0%Bet minimum
0−0.5%Bet minimum
+10% (breakeven)Bet minimum
+2+0.5%2× base bet
+3+1.0%4× base bet
+4+1.5%8× base bet
+5++2.0%+8× base bet (max)

Each true count point is worth approximately 0.5%. House starts at −0.5% at TC 0 with basic strategy. Player breaks even at TC +1, gains edge at TC +2 and above.

How rule variations affect the house edge

Not all blackjack games are equal. Rule variations can shift the house edge significantly. Always check the rules before sitting down.

Blackjack pays 3:2 (standard)−2.3% vs 6:5
Blackjack pays 6:5+1.4% to house edge
Dealer stands on soft 17 (S17)−0.22% vs H17
Dealer hits soft 17 (H17)+0.22% to house edge
Late surrender allowed−0.07% to house edge
Double after split allowed−0.14% to house edge
Re-splitting aces allowed−0.08% to house edge
Single deck−0.59% vs 6-deck

The single most important rule to avoid: 6:5 blackjack payouts. A table offering 6:5 on blackjack is 4–5× worse than a 3:2 table with basic strategy. Walk away.

Frequently asked questions

What are the odds of winning at blackjack?
With perfect basic strategy, players win roughly 42–44% of hands, the dealer wins 48–49%, and about 8–9% are pushes. Because pushes return your bet, the effective house edge is only around 0.5% — the best odds at any casino table.
What is the house edge in blackjack?
In a 6-deck S17 game with basic strategy, about 0.44–0.5%. Without basic strategy, 2–4%. Card counters with a solid bet spread can achieve +0.5–1.5% player advantage long-run.
What is the probability of getting a blackjack?
About 4.75%, or roughly once every 21 hands, in a 6-deck shoe. This payout at 3:2 contributes significantly to narrowing the house edge. Never take even money when you have a blackjack unless the true count is very high.
What is the probability of the dealer busting?
It varies by upcard. Dealer 5 and 6 bust most often (~42%), while dealer ace busts least (~12%). The 4–6 range are the weakest dealer upcards and are why basic strategy instructs you to double more aggressively and stand on stiff totals against them.
Does card counting improve your odds at blackjack?
Yes. Hi-Lo counting with perfect basic strategy and a reasonable bet spread can give the player an edge of 0.5–1.5%. The edge is small — it requires thousands of hands to realize — but it is mathematically real and the reason casinos bar known counters.
See the odds in action

The Blackjack GTO trainer tracks your running count and true count in real time, shows you your mistake rate, and explains every wrong decision. The best way to understand these odds is to practice until basic strategy is automatic.

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