21+3 Blackjack Side Bet | Complete Guide

The 21+3 blackjack side bet is one of the most popular side wagers in blackjack, allowing players to win big based on a three-card poker hand formed by their two dealt cards and the dealer’s face-up card. While it adds an extra layer of excitement to the game, understanding the odds, payouts, and house edge can help you make better betting decisions.

In this guide, we break down what 21+3 is, how to play, the probabilities of winning, and whether it’s worth the risk.

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🎯 What Is the 21+3 Side Bet?

The 21+3 side bet is an optional wager in blackjack that allows players to bet on the combination of their first two cards and the dealer’s face-up card. If these three cards form a winning poker hand, the player wins according to the payout table.

🃏 Winning Hands in 21+3 Blackjack

To win a 21+3 side bet, your cards must form one of the following poker-style hands:

• Pair Flush (2:1) – A pair of the same rank and suit (e.g., 6♦ 6♦).
• Flush (5:1) – Three cards of the same suit (e.g., A♥ 3♥ 9♥).
• Straight (10:1) – Three consecutive-value cards of any suit (e.g., 5♣ 6♦ 7♥).
• Three of a Kind (30:1) – Three identical-value cards of different suits (e.g., 2♥ 2♠ 2♦).
• Straight Flush (40:1) – Three consecutive-value cards of the same suit (e.g., 4♣ 5♣ 6♣).
• Three of a Kind Flush (100:1) – Three identical-value cards of the same suit (e.g., 7♠ 7♠ 7♠). This is the rarest and highest-paying hand in some versions of the game.

✅ The number of decks in play influences how often these hands appear. Most 21+3 blackjack games use six or eight decks, affecting the odds.

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🎮 How to Play Blackjack with the 21+3 Side Bet

1. Place Your Bets – Before the round starts, you place your main blackjack bet and optionally wager on the 21+3 side bet.
2. Cards Are Dealt – The dealer gives you two cards and reveals one of their own.
3. Winning the 21+3 Side Bet – If your two cards + dealer’s face-up card form a poker hand (e.g., a flush, straight, or three of a kind), you win the side bet.
4. Continue Playing Blackjack – The side bet result does not impact your regular blackjack hand; you still play out the round as normal.

🔎 Some blackjack variants also allow you to double down, split, or surrender even if you’ve placed the side bet.

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📊 21+3 Blackjack Side Bet Odds & Probabilities

The probability of winning a 21+3 side bet depends on the number of decks used and the payout structure. Here’s a breakdown of the likelihood of each hand appearing in a six-deck game:

Winning Hand	Probability	Payout
Pair Flush	1.12%	2:1
Flush	5.84%	5:1
Straight	3.10%	10:1
Three of a Kind	0.50%	30:1
Straight Flush	0.21%	40:1
Three of a Kind Flush	0.02%	100:1

💡 In most games, the total chance of winning any 21+3 side bet is around 9%, meaning the house has a significant advantage.

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💰 21+3 Blackjack Side Bet Payouts

While some tables offer a fixed 9:1 payout on all winning hands, most adjust the odds based on hand difficulty. Here’s a common payout structure:

• Pair Flush – 2:1
• Flush – 5:1
• Straight – 10:1
• Three of a Kind – 30:1
• Straight Flush – 40:1
• Three of a Kind Flush – 100:1

💵 The best payouts come from rare hands like a Straight Flush or Three of a Kind Flush, but these occur far less often than hands like a Flush or Straight.

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🎲 House Edge: Is the 21+3 Side Bet Worth It?

The house edge on the 21+3 side bet depends on the payout table and the number of decks in play. Here’s how it changes based on deck size:

• 3 decks – 7.76% house edge (worst odds)
• 6 decks – 4.14% house edge
• 8 decks – 3.18% house edge (best odds)

📌 For comparison, regular blackjack has a house edge as low as 0.5% with basic strategy, making it a much better long-term bet.

✅ Best strategy? If you’re playing for fun and excitement, the 21+3 side bet can be a thrilling addition. But if you’re focused on long-term profits, it’s not a smart bet due to the high house edge.

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❓ 21+3 Blackjack Side Bet FAQ

🔹 Is the 21+3 side bet worth it?

It depends on your goal. If you like high-risk, high-reward bets, it can be fun. However, the house edge is significantly higher than regular blackjack, making it a less strategic bet.

🔹 Can I count cards to improve my chances?

Not really. Since the side bet relies on poker hands rather than just card values, counting cards doesn’t provide much of an edge.

🔹 Do all blackjack tables offer 21+3?

No, but many online and live dealer blackjack games include it. Look for the 21+3 betting circle on the table or check the game description.

🔹 What’s the best payout table for 21+3 blackjack?

The best payout table is one that pays based on hand difficulty rather than a flat 9:1 for all wins. This allows for higher rewards on rare hands.

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🎯 Final Thoughts: Should You Play the 21+3 Blackjack Side Bet?

✔ Play it if:

• You enjoy high-risk side bets with big payouts
• You want to add more excitement to blackjack
• You’re okay with the high house edge

❌ Avoid it if:

• You prefer consistent, strategic play
• You’re trying to minimize losses
• You don’t like bets with low hit rates

📌 Best Strategy: If you want to try the 21+3 side bet, stick to tables with 8 decks and variable payouts, as they offer lower house edge and better returns on rare hands.