What Is 21+3 in Blackjack?
Updated
21+3 is a side bet settled from three cards: your first two plus the dealer's upcard. If those three make a poker hand, meaning a flush, a straight, three of a kind, or better, the bet pays. Payouts run from 5:1 up to 100:1, and on the standard paytable at eight decks the house keeps 3.70%.
- Three-card poker from your two cards plus the dealer's upcard.
- Payouts 5:1 to 100:1 on the common paytable.
- House edge 3.70% at eight decks, worse with fewer.
- The 5:1 flush does almost all the work, and almost all the damage.
How it is settled
Your two cards and the dealer's upcard are read as a three-card poker hand. The most common paytable, used by Evolution among others, looks like this.
| Combination | Payout |
|---|---|
| Flush, three cards of one suit | 5:1 |
| Straight, three consecutive ranks | 10:1 |
| Three of a kind | 30:1 |
| Straight flush | 40:1 |
| Suited three of a kind | 100:1 |
The 100-40-30-10-5 pattern is the one you will meet most often, though tables do vary and the differences are not cosmetic.
How often each one lands
Counted directly from the combinations, not simulated.
| Decks | Suited trips | Str. flush | Trips | Straight | Flush | House edge |
|---|---|---|---|---|---|---|
| 2 | 0.000% | 0.211% | 0.400% | 3.163% | 5.500% | 11.17% |
| 4 | 0.014% | 0.208% | 0.478% | 3.117% | 5.758% | 6.39% |
| 6 | 0.021% | 0.207% | 0.504% | 3.102% | 5.842% | 4.62% |
| 8 | 0.024% | 0.206% | 0.517% | 3.095% | 5.884% | 3.70% |
Suited trips are impossible with two decks, since the hand needs three copies of the same exact card. Method in how we calculate.
The shape of that table tells you where the money is. You will hit something about one hand in ten, and three fifths of those hits are the 5:1 flush. The 100:1 headline lands roughly once in four thousand hands, which at a normal pace is once every sixty or seventy hours at the table.
As with Perfect Pairs, more decks is better here. Eight decks give the rare, high-paying combinations enough room to occur, and those are what hold the edge down.
What it costs you
At eight decks the bet returns 96.30% and keeps 3.70%. Put that alongside a well-played main game at 0.44% and the side bet is charging you roughly eight times as much for each dollar wagered.
At six decks it climbs to 4.62%, and at two decks it reaches 11.17%. If you play 21+3 at all, an eight-deck shoe is the version worth playing.
Is it worth playing?
Not for a regular player. It is one of the more expensive things on a blackjack table, and unlike the main game there is no strategy to apply. You place it and it resolves.
There is a narrow exception. 21+3 can be attacked by a player running a separate side count of suits, since a shoe unusually rich in one suit raises the flush frequency, and flushes are most of the bet's value. That is genuinely difficult and rarely worth the effort next to counting the main game.
If you want to reduce what the house takes, basic strategy and then counting are where it happens, not here.
Where you will find it
Nearly everywhere. 21+3 is offered on most live dealer tables and on plenty of pit tables in Las Vegas and Atlantic City. It is always optional, and the main game plays identically whether you take it or not.
• Three-card poker from your two cards and the dealer's upcard.
• You hit about one hand in ten, usually the 5:1 flush.
• 3.70% at eight decks, 11.17% at two.
• Check the paytable, because trimmed ones cost double.
Keep reading
By Martin Kosek · every number on this site is computed by us, not copied.
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