Straight Flush Blackjack Odds and Winning Potential
The 21+3 side bet adds poker hands and video poker-style payouts to the game of blackjack. It means you can get a straight flush in blackjack and poker, and it’s not even the biggest payout on offer.
So, let’s pick apart 21+3 odds and payouts to see what you can win and how likely you are to win it when you play blackjack online for money.
Winning Poker Hands in the 21+3 Side Bet
In a typical game of blackjack, the most you can win is 3:2, which means you’ll get a total return of $50 for a $20 wager ($30 of which is profit). In some games, the payout falls to just 6:5 or 1:1, giving you even less. These are the payouts for a natural blackjack—a score of 21 with your first two cards.
Side bets like 21+3 enhance those payouts and give you a bigger target. This optional wager creates a mini poker hand out of the first three visible cards—both your and the dealer’s face-up cards.
Assuming the game uses standard rules and six decks, you can expect a payout that looks like this:
- Flush = 5:1
- Straight = 10:1
- Straight Flush = 30:1
- Three of a Kind = 40:1
- Suited Three of a Kind = 100:1
Blackjack Straight Flush Odds
Provided the above paytable is in play, the house edge for a six-deck blackjack game with these payouts comes to 13.39%. That’s considered very high, even for a side bet, but payouts and odds vary.
The odds of landing a straight flush with these rules are 0.2068%. It only applies to three cards, and a straight flush in such a format seems fairly achievable, especially if you’re used to playing video poker and chasing bigger odds with royal flushes. However, the odds are definitely not on your side.
Your chances are slim, but the high straight flush blackjack payout still makes it a tempting proposition for fans of this card game.
Other Odds and Payouts for 21+3 Wagers
A straight flush beats a three-of-a-kind in poker, but not in the 21+3 blackjack side bet. Three of a kind pays more, and if those cards are all of the same suit (such as 7h, 7h, 7h, as opposed to 7h, 7s, 7d), you will win even more.
The odds of hitting a suited three-of-a-kind are small, though, at 0.0207%.
How Some 21+3 Payouts Differ
The above paytable is just one example—many games offer different payouts and probabilities. It’s not uncommon to see 21+3 side bets that offer the same payout for all poker hands, regardless of their strength or probability. It means you’ll get less than the above paytable if you land a straight flush or three of a kind, but more for basic hands.
Although it seems counterintuitive, these side bets usually have a lower house edge, as those smaller “poker hands” are far more common than straight flushes and a three-of-a-kind.
Straight Flush Blackjack Odds in Top 3 Side Bets
The 21+3 side bet isn’t the only one that borrows hand values from poker. Many online blackjack games also have something known as Top 3. It also creates poker hands from the three face-up cards, but the difference is that the paytable focuses on the biggest three hands: straight flush, unsuited three of a kind, and suited three of a kind.
The straight flush pays 180:1 in most variations of this game, with the unsuited three of a kind returning 90:1 and the suited three of a kind triggering a jackpot payout of 270:1. The odds vary based on the number of decks, but they are similar to those discussed above for 21+3.
To learn more about this poker hand, read our guide to see how the Straight Flush pays in real games.
Conclusion: Landing a Flush in Blackjack
The straight flush is a big hand in blackjack and poker. But before you rush to place those side bets, make sure you check the odds, compare them to the payouts, and keep your bankroll and affordability in mind.
If you’re playing BetUS blackjack games for the first time, check out our 200% casino sign up bonus before you get started.
Blackjack Common Queries
What is a straight flush on blackjack?
It is three consecutive cards of the same suit and applies to side bets such as 21+3 and Top 3.
How rare is a straight flush?
It’s rare in both poker and blackjack, with odds of around 0.2% for the latter and 0.00139% for five-card versions of the former.
How do you hit a straight flush?
In blackjack side bets, your two cards and the dealer’s upcard need to be suited and connected, such as 7h, 8h, 9h.
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