Beating the 21+3 Blackjack: Here is how

One of the most common table games in any casino is Blackjack, and with the advent of online casinos, this game with various variants is now available online. So much so that platforms like Winissimo are always buzzing with players who want a piece of the Blackjack action. The game has its nuances, characteristics and attractive features. 

21 + 3 Blackjack is a common side bet that can be put in the classic casino beside your initial bet. It offers some enticing odds, by combining Blackjack and Three-card Poker.

Beating the 21+3 Blackjack: Here is how

How to play 21+3?

You bet on whether the first two cards in your hand and the dealer’s face-up card combine to create one of the three-card poker hands mentioned below in the 21 + 3 Blackjack side bet:

  1. Flush – Three cards in a matching suit
  2. Straight- Three successive values of cards, such as 4-5-6. Aces may be low or high
  3. Three of a kind – Three cards of the same face/value card
  4. Straight flush – Three consecutive cards with values all in the same suit
  5. Suited three of a kind – Three cards of the same suit and same face/value card

Before your cards are dealt out, you have to put the bet. 

There will normally be a 21 + 3 box on the table where you put your stake for the side bet. If your first two cards and the dealer’s up-card combine to give you one of the above-mentioned hands then you win the 21 + 3 Blackjack bet. 

If you don’t, you forfeit your stake in a side bet. How much you win depends on the three-card hand you get, with various odds being paid for each, and varies from operator to operator. 

It’s always advisable to double-check the 21+3 Blackjack odds at the particular land-based or online casino (live Blackjack) where you plan to try out the side bet. The payout on both of these was 9-to-1 in the original edition. With this paytable, the game has a 3,2386% home advantage. 

New pay tables, which have higher house edges and better volatility, have recently been launched. In case of targeting flushes, the player is favoured by some heavy imbalance in the suits.

Consider, for example, a case where there are 40 cards, 10 for each suit. The number of possibilities to make a three-card flush is 480 without getting into the math. Take the same 40 cards now, and say that 15, 10, 10, 5 are spread. Then 705 is the number of three-card flushes. The more the allocation of suits is unbalanced, the more the edge swings towards the player.

Probabilities and House Edge Rates for the 21 + 3 Side Bet

You will be probably curious at this stage how likely or unlikely it would be to catch one of those qualifying three-card poker hands if you’re a pessimist by default. That is a fantastic question, so please continue reading this article to find the answers:

Beating the 21+3 Blackjack: Here is how

21 + 3 Side Bet Combos, Probabilities, and Expected Return Rates





Straight Flush


0.20 %


Three of a Kind


0.52 %




3.10 %




4.72 %


Pair + Flush


1.12 %


Pair (no flush)


19.49 %




70.83 %






The most probable outcome when making a 21 + 3 side bet is to land a non-qualifying hand, as you can see from the data above. Just under 71% of the time, you will make nothing at all, with slightly under 20 % of deals ending in one pair, but not enough to create a winner.

With that said, with a flush being the most possible winner at a 4.72 clip, nearly 10% of all hands would end in a 9 to 1 payout.

The next most possible result from there is hitting a straight (3.10%), followed by a combo of one pair + flush (1.12%), then three of a kind (0.52%), and eventually the straight flush (0.20%).

The lower right-hand entry in the table above reveals a 3.24 % house edge average on each 21+3 side bet put when you add it all up. That’s a tad higher than the 0.50 % average house advantage faced by simple Blackjack strategy play, but when it comes to casino table games, it’s still far inside the scope of respectability.

Traps to Watch Out for When Playing the 21 + 3 Side Bet

All the details given so far on this page applies to the standard 21 + 3 edition. That means 9-1 payouts on both winners, and the dealer uses a six-deck foot.

Unfortunately, to tilt the probabilities even further in the house’s favour, the casino industry loves to tinker with fair side bets. For that cause, if you see the 21 + 3 side bet distributed in ways that deviate from the 9 to 1, six-deck shoe model, you should remain cautious.

For example, you could discover that a specially shaped shoe is used under the casino’s house rules for Blackjack. Some online Blackjack platforms tend to use a shoe with four decks, while others look for an option with eight decks.

As a general rule of thumb, you’ll see the house edge on 21 + 3 side bets going up if the shoe includes fewer decks, which is bad news for the player.

Beating the 21+3 Blackjack: Here is how

How to beat the Blackjack 21+3 side bet?

  • Assuming you’ve placed the side bet, you’ll get paid out if you have hit anything with those three cards. If you haven’t, you’ll lose your bet and carry on with your game of Blackjack. These payouts seem amazing, but the odds of actually hitting that flush, let alone anything else, is pretty low. Like all side bets, the house edge is usually pretty high. 
  • The payouts may seem attractive and make you go up, but without any solid plan your hard-earned money might get flushed away. Unless, of course, you have a strategy. And we’re not talking about a run-of-the-mill betting strategy. We’re talking about card counting.
  • If you are new to card counting, then you can be intimidated by it. But there is nothing to worry about. Just as you can use the doubling down feature for your benefit in the correct situations, you can use card counting too.
  • Trying to count cards in your head with so much confusion surrounding you, all the while trying to avoid being spotted by the pit boss, isn’t exactly easy.
  • But while it is difficult to count cards, particularly because you have to keep track of different numbers, it is much easier to count suits.
  • Begin by selecting a suit. For argument’s sake, let’s pick diamonds. You can start with the number 0. Subtract 1 from your limit each time a diamond is dealt with. Add 1 to your count any time four cards are dealt out. That’s one shoe as 52 cards are dealt. Divide your present count by how many decks are left in the shoe. It’s prime time for putting the side bet when the count reaches either +4 or -5.
  • You’ll find it’s super easy to count suits when the count doesn’t mess too much with the number hitting the felt. The only thing is, you limit yourself to winning with just 25 % of the cards in the shoe by counting just one suit. As part of a team, consider counting for that purpose. Only aim to stop being caught.
  • It is important to keep track of the number of cards in each suit left in the shoe to make sense of this. A team of counters, each keeping track of one of the suits (or by a mentally gifted single counter) will achieve this. Then the counters measure the difference between the most plentiful suits and the least plentiful. This difference is then converted into a true count, and the player has an edge if the true count is sufficiently large.

Here are some pointers to keep in mind about the 21 + 3 side bet:

  • Look out for the version of Blackjack you are playing( either it is American or European Blackjack), as different versions may have different rules as per their set-ups.
  • Look out for solo players who only play this bet during a shoe at some moments, and when they play, it’s a maximum bet. A shuffle monitoring technique could be used by these players.
  • Look for a team of players who can play the full wager at the same time on this bet. A card counting method can be used by these players.
  • If the game is hand-shuffled, try a new shuffle or rent an automatic shuffle if the shuffle is theoretically trackable.


Now that you know the ins and outs of the most common side bet of Blackjack, it’s up to you to determine whether or not your alley is up for the added game. Budget a few bucks on the side to try the 21 + 3 side bet for yourself the next time you visit any online casino for some Blackjack action.

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