21+3: a three-card poker hand on top of your blackjack
The 21+3 side bet scores your two cards plus the dealer’s upcard as a three-card poker hand: it pays on a flush, straight, three of a kind, straight flush, or suited three of a kind. The classic version pays a flat 9:1 on any qualifying hand; the tiered version trades a bigger top prize for a worse overall return.
It is the least bad of the common side bets — which still makes it several times more expensive than the blackjack hand it rides on.
House edge
3.24% per unit bet (6 decks, pays 9:1 on any hand). For contrast: the blackjack hand underneath it costs about 0.5% with perfect basic strategy — this side bet is roughly 6× more expensive per unit wagered.
At 5 units per hand and 70 hands an hour, 21+3 costs about 11.34 units per hour on top of the main game.
Odds and payouts
| Outcome | Pays | Chance | Odds |
|---|---|---|---|
| Suited three of a kind | 9:1 | 0.0207% | 1 in 4,821 |
| Straight flush | 9:1 | 0.21% | 1 in 484 |
| Three of a kind | 9:1 | 0.50% | 1 in 198 |
| Straight | 9:1 | 3.10% | 1 in 32 |
| Flush | 9:1 | 5.84% | 1 in 17 |
| Anything else — you lose | −1 | 90.32% | — |
House edge: 3.24% — the bet wins something on 9.68% of hands.
| Outcome | Pays | Chance | Odds |
|---|---|---|---|
| Suited three of a kind | 100:1 | 0.0207% | 1 in 4,821 |
| Straight flush | 40:1 | 0.21% | 1 in 484 |
| Three of a kind | 30:1 | 0.50% | 1 in 198 |
| Straight | 10:1 | 3.10% | 1 in 32 |
| Flush | 5:1 | 5.84% | 1 in 17 |
| Anything else — you lose | −1 | 90.32% | — |
House edge: 4.62% — the bet wins something on 9.68% of hands.
Does the deck count change it?
| Shoe | Pays 9:1 on any hand | Pays 100 / 40 / 30 / 10 / 5 |
|---|---|---|
| 1 deck | 13.30% | 18.21% |
| 2 decks | 7.26% | 11.17% |
| 4 decks | 4.24% | 6.39% |
| 6 decks | 3.24% | 4.62% |
| 8 decks | 2.74% | 3.70% |
Frequently asked questions
What is the house edge of 21+3?
With the classic 9:1 paytable and 6 decks, 3.24%. A well-played blackjack hand at the same table costs around 0.5% — the side bet is roughly 6× more expensive per unit wagered.
How often does 21+3 win?
A qualifying hand arrives on 9.68% of rounds — about 1 in 10.
Check these odds against your casino’s rules →
The free analyzer recomputes every side bet for your exact deck count and paytable,
alongside the optimal basic strategy for the main game.