Blackjack Calculator

One of the keys to beating the casino is knowing how large their initial advantage is against you. It’s important to know your odds on blackjack. Use this blackjack calculator to see how various rules affect the casino’s advantage.

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Note: If the output is negative, that means the player has the advantage off the top.

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Remember that this is assuming perfect basic strategy. With Hi-Lo card counting, the player’s advantage goes up by about .5% for each positive true count. So if it says “0.50”, then the player will have an advantage starting at a true 1, a .5% advantage at a true 2, and a 1% advantage at a true 3. Conversely, the casino would have a 1% advantage at a true -1. Below is a chart that shows how each rule affects the house edge.

Rule Change in House edge
one deck 0.00%
two decks 0.32%
four decks 0.47%
six decks 0.52%
eight decks 0.55%
Hit 17 0.20%
Double after Split -0.14%
Double 10 & 11 only 0.17%
Double 9, 10, & 11 only 0.08%
Re-split aces -0.08%
late surrender -0.08%
early surrender -0.71%

As published in Professional Blackjack. Stanford Wong. Pi Yi Press 1994

So What Exactly Is The House Edge?

So, now you understand certain rules can raise and lower the house edge, as illustrated above, and most people already get the idea that the house edge means “the house always wins.” Even still it can be tricky to really understand what the house edge really means. Confusion on this subject is extremely pervasive among casinos patrons, so what does the house edge mean in real-people terms?

Essentially the house edge is expressing the percentage of each bet the house will get to keep if you made that bet a million times.

Let’s use an example. Let’s say the house edge is half of one percent like it is on most blackjack games. If you were betting 100 dollars on each round and you played 100 rounds an hour, you would be betting a total amount of $10,000 worth of individual bets every hour. If you kept betting that way for 10,000 hours of blackjack that means you placed $100 million worth of individual bets, added together. The house edge is half of one percent so if we take $100 million and multiply it by .005 we get $500,000 which is how much the casino expects to make off of you in the long run if you continue to bet $100 a hand. So essentially each bet you make is worth about 50 cents to the casino. Obviously you don’t just hand over 50 cents every round. That wouldn’t be any fun for a gambler, and nobody would play if they didn’t stand to win something in the short run, but that’s how much each bet would cost you in the long run. In the short run you’re either going to win $100 bucks or you’re going to lose $100 bucks. But to the casino, they just made 50 cents.

We know what you’re thinking, “nobody plays 10,000 hours of blackjack.” You would be correct and that’s a good thing considering how expensive that would be. But for the casino, you aren’t the only one placing bets. Maybe you won’t play 10,000 hours in your lifetime, but there are certainly enough people in the casino betting like you do to get several thousand hours’ worth of bets within a reasonable period of time (depending on the size of the casino) especially since most casinos are taking bets 24/7. And believe us when we tell you it doesn’t take 10,000 hours to lose big to the casino.

So in the short term, players win and players lose, but in the long term you cannot escape the math and the casino will wait patiently for your luck to run out because they know their house edge is guaranteed in the long run. If they don’t make their money on you, they’ll make money on the guy sitting next to you until it’s your turn. The only way around this is to become a card counter and flip the house edge against the casino.

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Other Factors that Contribute to game quality:

Shoe Penetration: A low initial house edge is important when it comes to beating the game of Blackjack with card counting but the rules of the game are only part of the picture when it comes to actually BEATING blackjack. Penetration is one of the biggest factors that will determine how big of an edge you can hope to gain over the house. Penetration is either expressed as the number of decks cut out of play or the percentage of cards that are actually dealt. For instance, a 6 deck game that is cutting off 1 deck of cards could be expressed as “1 deck of pen” or “83% Pen” because 83% of the cards will be dealt out before the shuffle.

Below is a comparison chart of a standard 6 deck game of blackjack using a 1 to 12 spread and a $15,000 bankroll.

6 Deck, Hit17, Double after Split, Re-split Aces

Game 6 deck 6 deck 6 deck 6 deck 6 deck 6 deck
Spread 1 to 12 1 to 12 1 to 12 1 to 12 1 to 12 1 to 12
Bankroll $15,000 $15,000 $15,000 $15,000 $15,000 $15,000
Decks cut off 0.75 Pen 1 Pen 1.25 Pen 1.5 Pen 1.75 Pen 2 Pen
Hourly EV $25.73 $21.11 $17.03 $13.68 $10.47 $7.84
Risk of Ruin 0.80% 1.30% 2.20% 3.60% 6.10% 10.10%

Notice how the fewer decks you cut out of play, the greater the win rate and the smaller the risk. All of the rules are identical and the spread is identical in each scenario but this game can go from insanely good to unplayable just by where the dealer puts that silly little plastic card. Just in a 1.25 deck difference, from 0.75 cut off to 2 decks cut off, your risk of ruin increases more than tenfold and your earnings are less than half.

This principle is the exact reason why CSMs are not vulnerable to card counting. A CSM game is the equivalent of cutting off 5 decks of a 6 deck shoe! To read more about CSM’s check out our blogpost “Are Continual Shuffle Machines Making Card Counting Obsolete?”