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21+3 Blackjack Side Bet
21+3 mixes blackjack with three-card poker. Your first two cards and the dealer’s up card make a poker hand, and the better the hand, the bigger the payout.
How 21+3 works
- Before the deal, put a bet on the 21+3 box next to your main bet.
- After the deal, your first two cards plus the dealer’s face-up card form a three-card hand.
- If the three cards make one of the poker hands below, you win straight away. Otherwise the side bet loses.
- Your main blackjack hand carries on as normal.
The name comes from the two games: 21 is blackjack, and 3 is three-card poker.
21+3 payouts
| Hand | What it means | Example | Pays |
|---|---|---|---|
| Flush | All three cards the same suit | 2♠9♠K♠ | 5:1 |
| Straight | Three ranks in a row, any suits | 7♣8♥9♦ | 10:1 |
| Three of a kind | Three cards of the same rank | Q♣Q♥Q♠ | 30:1 |
| Straight flush | A straight, all in one suit | 5♥6♥7♥ | 40:1 |
| Suited trips | Three identical cards | A♦A♦A♦ | 100:1 |
Aces count high or low, so A-2-3 and Q-K-A are both straights. K-A-2 isn’t. Card values from blackjack don’t matter here: 10-J-Q is a straight, but 10-10-J is nothing.
21+3 odds (6 decks)
We counted every possible three-card combination from a six-deck shoe: 5,013,320 of them. These are the exact odds of each 21+3 hand:
| Hand | Chance | About 1 in | Pays |
|---|---|---|---|
| Suited trips | 0.021% | 4,821 | 100:1 |
| Straight flush | 0.207% | 484 | 40:1 |
| Three of a kind | 0.504% | 198 | 30:1 |
| Straight | 3.10% | 32 | 10:1 |
| Flush | 5.84% | 17 | 5:1 |
| Any winning hand | 9.68% | 10 | |
| No hand (bet loses) | 90.32% |
House edge
On this paytable the 21+3 bet has a house edge of 4.62%. Over time you’d expect to get back about 95 chips for every 100 you bet. That’s lower than many casino side bets, but still much higher than the main blackjack game played with good strategy.
Three of a kind pays 30:1 but turns up less than once in 198 hands, while flushes come up about once in 17. Most of your 21+3 wins will be flushes and straights.
21+3 tips
- It’s settled before you play. The dealer’s second card isn’t used, and your later cards don’t count, so your blackjack decisions can’t affect it.
- Combine it with Perfect Pairs. A pair in your first two cards can also make three of a kind or suited trips with the dealer’s card, so both side bets can win on the same deal. See the Perfect Pairs guide.
- Keep side bets small next to your main bet. They lose about 9 times in 10.
21+3 FAQ
How does 21+3 work in blackjack?
21+3 takes your first two cards and the dealer’s face-up card and treats them as a three-card poker hand. If those three cards make a flush, straight, three of a kind, straight flush or suited trips, the side bet wins.
What is the best hand in 21+3?
Suited trips, three identical cards with the same rank and suit, is the top hand and pays 100:1. With six decks it comes up about once in every 4,800 hands.
Does an Ace count high or low in 21+3?
Both. A-2-3 and Q-K-A are both straights. A straight can’t wrap around the corner, so K-A-2 is not a straight.
What are the odds of winning 21+3?
With six decks, a 21+3 bet wins about 9.7% of the time, roughly 1 in 10 hands. Most wins are flushes (5.8%) and straights (3.1%).