Guide to Blackjack in Vegas 21 + 3 Side Bet

Blackjack is the most loved table game in Las Vegas casinos. It’s a favorite among both novice gamblers as well as seasoned strategists.

Blackjack’s skill-based nature allows players to know basic strategy and play every hand flawlessly. Even though you will still lose some hands and win some, playing optimal blackjack games reduces the house edge to 0.50 percent. This is based on standard Sin City rules.

Blackjack is also easy to learn even for beginners. Anyone with a basic understanding of the 52-card deck can give it a try. Blackjack is a great entry point for novice gamblers who just want to have fun.

You’ll find more options than just standard 21 when you play this classic card game at Las Vegas casinos.

Modern blackjack has many side bets, or optional wagers, that can be played along with your standard hand. This allows for more variety and spice. Side bets, which offer huge returns for minimal wagers, are a great way to make big wins.

Blackjack side bets don’t always produce big wins. Depending on which side bet you choose, an additional chip can help you win a few during each hand.

Blackjack experts often mock people who like side bets and call them “suckers”, who don’t understand what they are getting themselves into. Yes, it is true that I understand the perspective of someone who gambles like a robot, playing optimal strategy at all time.

To sum it all, I gamble to have fun at the table. Entertainment and camaraderie are more important than perfect play. While I do still follow basic strategy guidelines when I play my base hand, I don’t hesitate to make side bets when I feel the need.

This page is for those who enjoy side betting on Blackjack . Here are detailed guides that will explain the rules, payouts and probabilities of several commonly-spread blackjack side bets in Las Vegas.

Introduction to the 21 + 3 Side Bet

Blackjack’s most popular side bet, 21 + 3, was first rolled at the Las Vegas Hilton (now the Westgate) in 2001.

The “+3” part of the title indicates that 21 + 3 is a side wager based on your two-card starting hand and the dealer’s lone card. You’ll get a 9-to-1 payout if your three cards combine to make qualifying three-card poker hand.

Here’s how it works…

After you have placed your ante for the base game, you may also place a second wager on the special 21 +3 logo that is emblazoned on felt. The base game is identical to regular blackjack. You don’t need to worry about any deviations to the rules or gameplay.

You’ll know if your 21 + 3 side wager has won or not after the dealer hands you your cards.

Also Read: Can You Still Find $5 Blackjack?

How to land a winner on the 21 + 3 Side Bet

These are the five qualifying poker hands that will trigger a 9-to-1 payout on this side bet.

21 + 3 Side Bet Qualifying hands


Straight Flush Three cards in succession of the same suit (6-8 of hearts; etc.

Three of a kind Three cards of the same rank (Q-Q-Q, etc.)

Straight Three consecutively ranked Cards (6-7-9 from different suits; etc.

Flush Any three cards from the same suit (2-2-7-Q of heart; etc.

Pair + Flush Any two cards with the same rank plus all three cards that are suited (6-6-Q suit, etc.).

You’ll receive a 9-to-1 payout if you match your two-card starting hand and the dealer’s up to create any of the combinations above.

The best thing is that the outcome of your base blackjack wager has no effect on the 21 + 3-side bet. This means that you can either win a lowly 14 or go bust. Or, the dealer could flip up a natural 21.

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

You might be wondering if it is possible – or even impossible – to land one of the three-card qualifying poker hands. This is a great question. Check out the table below for the answers.

21 + 3 Side Bet Combos and Probabilities


Straight Flush 10,368 0.20 Percent 0.018613

Three of a kind 26,312 0.52 per cent 0.047236

Straight 155,520 3.10% 0.279192

Flush 236,736 4.72 Percent 0.424993

Pair + Flush 54,160 1.12 percent 0.100819

Pair (no flush), 977,184 19.49% -0.194918

Nothing 3551,040 70.83% -0.708321

Total 5,013,320 1.00-0.032386

The most likely outcome of a 21 + 3 side betting is to win a non-qualifying hand, as you can see from the above data. The odds of you winning nothing are just below 71 percent. Only slightly less than 20 percent of deals will result in a pair of cards, but not enough for you to win.

The next most likely outcome is a straight (3.10%) followed by a combination of one pair and flush (1.12%), then three of the same (0.52%), and finally the straight flush (0.20%)

Add it all together, you will see that the lower left-hand entry in this table shows a house advantage rate of 3.24 percent for every 21+ 3 side bet. This is slightly higher than the 0.50% average house edge for basic blackjack play but still within the realms of acceptable casino table game performance.

Take this as an example: When you spin a double zero roulette wheel in Sin City there is a 5.26 percent house edge. Double-zero Roulette, just like the 21 + 3-side bet, is pure chance. However, gamblers of all walks still love to take a chance on their number or colors. The same goes for slots. They have an average house edge of 5-9 percent, depending on which game they are playing and the features that they offer.

If fun is your goal, it’s worth adding some intrigue to your blackjack game at a cost only 3.24 percent.

There are some things to be aware of when playing the 21 + 3 Side Bet

This page contains information about the standard version 21 + 3, as published by Galaxy Gaming.

This means that 9 to 1 payouts are available for all winners and a dealer can use a six-decker shoe.

The casino industry loves to play with side bets to increase the house edge. You should be cautious if you see the 21+3 side bet spread in ways other than the 6-deck, nine-deck shoe model.

You might find that the house rules for blackjack at a casino use a different size shoe. Some casinos prefer to use a 4-deck shoe while others choose an 8-deck option.

The house edge on 21 side bets and 21 of the decks in a shoe will increase if it contains decks or fewer.

Another trick used by casinos to lure unsuspecting gamblers who enjoy wagering on 21 + 3 action is the offshoot called “Xtreme.” This is where the house hopes a modified pay table will hook players in and punish them with high house edge rates.


Xtreme 21 +3 Side Bet Combos, Probabilities and Expected Returns


Straight Flush 30 to 1 10,368 0.20 Percent 0.062043

Three of a kind 20 to 1 26,312 0.52 per cent 0.104968

Straight 10 to 1 155,520 3.10% 0.310214

Flush 5 to 1, 292, 896 5.84 Percent 0.292118

Nothing -1 4,528.224 90.32 Percent -0.903239

Total N/A 5,013,320 1.0000 -0.133896

You can see that the Xtreme 21 + 3-side bet has a sweet payout of 30 to 1, which is more than the straight flush. The elusive straight flush is not possible on less than one-fifth (1%) of all deals. This makes it an unstarter.

However, if you make the best of the 21 + three qualifying hands, the basic flush then your payout will drop to 9 to 1.

The house edge against you increases to 13.39 percent when you bet on the Xtreme 21+ 3 side bet. This is more than four times the standard 21 + 3 side betting, making the Xtreme version one of the most dangerous options on any table game floor.


You now have a better understanding of the most popular side bet in blackjack. Now it is up to you whether the additional gamble suits you. If I feel lucky, I will take a gamble on the extra wager. A 3.24 percent house advantage is acceptable in the context of long-shot gambling. Spend a little extra money next time you’re in Las Vegas to play blackjack.

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