What Changes the House Edge in Blackjack?

One of the main reasons blackjack is such a popular game is that the house edge – by which we mean the casino’s advantage over the player – is, generally speaking, very low when compared to other casino games. However, many online casinos have lots and lots of different versions of blackjack, many of these featuring slightly different rules in terms of what you can and can’t do, what the dealer does and even things like the number of decks of cards used.

Whilst some online casinos will tell you the precise house edge for whatever game you are playing, some won’t – even if you ask them outright – either because they themselves don’t know or because they just don’t divulge that information.

However, to help you pick the version of blackjack that will give you the greatest chance of winning, here we take a look at the different factors that have an impact on the house edge.

Number of Decks

The fewer the number of decks, the better things are for the player. One deck is great if you can find it but each added deck increases the house edge. For example, all other factors being equal, the jump from four to eight decks changes the casino’s advantage from 0.45% to 0.53% under certain rules, which might not sound like a lot but over the course of hundreds of hands that soon adds up.


Never play blackjack in a game where the payout for hitting the hand of blackjack is less than 3/2. Some casinos pay at 6/5 instead which turns the house edge of 0.53% above into a whopping 1.88% – more than three times as big!

Split Aces

Few casinos let you hit split aces but if you can, our 0.53% edge drops to just 0.34%.


Being able to double on any total is the best option, followed by 9-11 and lastly 10 and 11 only, although the impact of this is relatively small. Not being able to double after a split has a relatively large impact on the house edge, for example turning 0.53% into 0.66%.

Soft 17

If the dealer hits on soft 17 stay away, as this would turn a house edge of 0.53% into a much larger 0.75%.

Other Factors

Other factors that increase the house edge are being able to re-split to just two, rather than more hands, not being able to re-split aces, and not having a surrender rule compared to the rarely found late surrender.

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