21+3 Side Bet: Poker on Your Blackjack Table

Walk up to almost any blackjack table in Las Vegas, Atlantic City, Macau, or a live-dealer studio, and you will see a small extra betting circle next to the main one, usually labeled 21+3. It is the most widely deployed blackjack side bet in the world, and it is popular for a simple reason. It turns every deal into a three-card poker hand, so you get a second chance at a payout before you make a single hitting or standing decision.

I'm Marcus Vance, and my job is to tell you what a bet actually costs before you put chips on it. This guide covers how 21+3 works, the two main paytables, how often each hand appears, and the true house edge. It also shows how much the bet adds to your hourly loss rate. By the end, you will be able to read a 21+3 placard and know within seconds whether the bet is merely expensive or truly costly.

What Is the 21+3 Side Bet?

21+3 is credited to Geoff Hall. It was licensed and rolled out widely, and today it appears on brick-and-mortar tables and in nearly every major live-casino studio. The idea is easy to follow:

• Before the deal, you place a wager in the 21+3 circle alongside your main blackjack bet.
• Your first two cards plus the dealer's upcard form a three-card poker hand.
• If that three-card hand makes a qualifying poker combination, the side bet pays. If not, the dealer collects it.
• The side bet is settled right away. It has nothing to do with whether your blackjack hand later wins, loses, or pushes.

The qualifying hands come from three-card poker rankings:

• Flush: all three cards share a suit, such as 2♥ 9♥ K♥.
• Straight: three consecutive ranks in mixed suits, such as 7♣ 8♦ 9♠. The ace plays high or low (A-2-3 and Q-K-A both count), but straights cannot wrap around, so K-A-2 does not count.
• Three of a Kind: three cards of the same rank, such as 6♠ 6♦ 6♣.
• Straight Flush: consecutive ranks in a single suit, such as 10♦ J♦ Q♦.
• Suited Three of a Kind: three identical cards, such as Q♠ Q♠ Q♠. This hand is only possible because shoes contain multiple decks.

Pairs do not pay. A suited pair, such as 7♥ 7♥ K♥, is paid as a flush on most tables.

The Two Paytables You Will Actually Encounter

There are minor regional variants, but nearly every 21+3 game you will see uses one of two structures. They look very different on the felt, and they produce noticeably different costs.

1. The Original Flat Paytable (9 to 1 on Everything)

The classic version pays a flat 9 to 1 on any qualifying hand. A straight flush pays the same as a flush, and three of a kind pays the same as a straight. It is plain and easy to explain, and it is the cheapest version of the bet.

• Straight Flush: 9 to 1
• Three of a Kind: 9 to 1
• Straight: 9 to 1
• Flush: 9 to 1

House edge: 2.74% with 8 decks and 3.24% with 6 decks.

2. The Modern Tiered Paytable (100 / 40 / 30 / 10 / 5)

This is the version you will see on most of the Las Vegas Strip, on Evolution's live tables, and in Pragmatic Play Live studios. It is often marketed as "21+3 Xtreme" or simply shown with a large "100 to 1" headline.

• Suited Three of a Kind: 100 to 1
• Straight Flush: 40 to 1
• Three of a Kind: 30 to 1
• Straight: 10 to 1
• Flush: 5 to 1

House edge: 3.70% with 8 decks, about 4.6% with 6 decks, and about 6.4% with 4 decks.

House Edge Comparison by Paytable and Deck Count

Deck count matters in both versions, and in the same direction: more decks favor the player. The reason is card removal. Once your first card is dealt, the shoe holds one fewer card of that suit and rank. In a 4-deck shoe, that removal is a meaningful share of the remaining matching cards. In an 8-deck shoe, it barely registers. Flushes, trips, and suited trips therefore become more likely as the shoe gets bigger. This is the opposite of the main blackjack game, where fewer decks generally help you.

A note on the numbers you will see quoted elsewhere. Lower tiered-paytable figures for 6 and 4 decks circulate widely online, often 4.14% and 6.29%. When I run an exact combinatorial count of every possible three-card hand under the 100/40/30/10/5 schedule, the 8-deck result lands squarely on 3.70%. The 6-deck and 4-deck results, however, come out at roughly 4.62% and 6.39%. If a source's figures look friendlier than these, assume it is using a slightly different paytable or rounding generously.

You do not have to take my word for any of it. The full enumeration is laid out in the 21+3 combinatorial math and EV derivation on BlackjackMath.org. You can also plug your own paytable into the house edge mathematical calculator on BlackjackMath.org to check any variant you run into.

Exact Hit Frequencies: How Often 21+3 Actually Pays

Marketing material shows you the payouts. It never shows you how often they happen. Here is the exact frequency of each 21+3 outcome in a standard 8-deck shoe, the most common configuration in live-dealer studios and on many Strip tables. Each category is mutually exclusive: a straight flush is not also counted as a straight or a flush.

Here is what that table means at the felt. You will lose the 21+3 bet about nine times out of ten. A typical hour at a busy table is around 60 to 80 rounds, so you can expect six to eight winning side bets in that hour. Most of them will be flushes paying 5 to 1 on the tiered table.

Long dry spells are normal, not a sign that a win is due. A run of 30 or 40 straight losses happens regularly to every 21+3 player. The suited-trips jackpot appears roughly once every 4,000 rounds. For a recreational player who logs about 70 rounds an hour, that is about once every 58 hours of play.

The Bankroll Destruction Factor

A house edge of 3.70% may not sound alarming on its own. Its real impact shows when you compare it with the game you actually came to play. A good shoe game with standard rules and perfect basic strategy runs a house edge of roughly 0.4% to 0.6%. The 21+3 side bet is six to fifteen times more expensive per dollar wagered than the blackjack it sits next to.

Here is a realistic scenario: a $25 main bet, a $5 side bet, 70 rounds per hour, and a 0.50% edge on the main game.

A $5 chip is only 17% of your total action on each hand, yet it more than doubles your expected hourly loss in every configuration in the table. Even the most player-friendly version, the flat 9 to 1 game on 8 decks, adds over 100%. The worst common setup, a tiered paytable on a 4-deck shoe, makes your session cost more than three and a half times what straight blackjack would.

The same logic applies to a whole weekend. Four hours a day for three days at a tiered 6-deck table costs about $194 in side-bet expectation alone. That is more than the entire expected loss from your $25 blackjack action over the same period.

Can 21+3 Be Beaten?

In theory, every side bet that is dealt from a shoe has some sensitivity to which cards have already been played. Because 21+3 depends heavily on suits, a shoe that is left heavy in one suit slightly raises the chance of a flush. In practice, the effect is small. You would have to track all four suits at once, plus rank clusters for straights and trips, and the bet only rarely turns positive.

Live-dealer games usually deal deep into 8-deck shoes or reshuffle continuously. Some studio formats, such as the one covered in our Infinite Blackjack guide, effectively generate fresh shoes. For practical purposes, treat 21+3 as a fixed-edge bet you cannot overcome. Players who want to put time into an actual advantage are much better served by card counting on the main game, which pays off far more reliably for the effort.

Auditing Your Table Before You Bet

Paytables differ from casino to casino and even from table to table on the same floor, so check before you bet. Our Side Bet Auditor tool was built for this. Enter the payout for each 21+3 hand and the number of decks, and it returns the house edge plus your expected cost per hour at your own bet size and pace. Here is my audit routine:

1. Read the placard and the flush line first. A 9 to 1 flush means the original flat table. A 5 to 1 flush means a tiered table.
2. Confirm the deck count. Ask the dealer or check the game info panel online. For this bet, 8 decks are better than 6, and 6 are better than 4.
3. Enter both into the Auditor. Note the house edge and the dollar cost per hour.
4. Compare it with your main game. If the side bet costs more per hour than your blackjack action, you are paying a premium for entertainment. Decide deliberately whether it is worth it.
5. Compare it with other side bets on the table. Our Perfect Pairs side bet audit and Bust It side bet audit show that some side bets cost even more than 21+3. None of the common ones comes close to the main game.

Where 21+3 Fits in the Bigger Picture

21+3 is not the worst bet in the casino. It is clearly better than keno, most slot machines, and several novelty side bets. But blackjack is one of the few games where a disciplined player can get the house edge under half a percent, and adding a bet with a 3% to 6% edge undoes much of that work.

If what you want is variety and bigger swings, there are better options. Some blackjack variants build their extra features into rule structures that cost less than this side bet. Our Blackjack Variants overview ranks the ones that keep the house edge reasonable while still offering more action than standard blackjack.