21+3 — odds, paytable and the exact house edge
21+3 makes a three-card poker hand from your two cards plus the dealer’s upcard: flush, straight, three of a kind, straight flush or suited trips. It is the best-designed side bet on most tables — which still leaves it costing seven times the main game.
Exact probabilities (8 decks)
| Hand | Pays | Combinations | Probability |
|---|---|---|---|
| Suited three of a kind | 100:1 | 2,912 | 0.024% |
| Straight flush | 40:1 | 24,576 | 0.206% |
| Three of a kind | 30:1 | 61,568 | 0.517% |
| Straight | 10:1 | 368,640 | 3.095% |
| Flush | 5:1 | 700,928 | 5.884% |
| Any win | — | 1,158,624 | 9.726% |
House edge at this full paytable: 3.704%, exact for an eight-deck shoe. Watch for degraded versions — some tables trim the straight to 9:1 or the flush’s role entirely; every trimmed unit lands on the most frequent winners and inflates the edge fastest. The bet resolves on the deal, before any decision you make — no strategy, no skill, only the shoe. The dealer’s upcard doing double duty is a nice piece of design, not an exploitable one: its real informational value belongs to the main game.
Frequently asked
How often does 21+3 win?
With eight decks, ${sbp(TP.win / TP.tot)} of hands — dominated by flushes (${sbp(TP.flush / TP.tot)}) and straights (${sbp(TP.straight / TP.tot)}). The premium hands above 30:1 land less than once in 130 hands combined.
What is the house edge of 21+3?
Exactly ${sbp(e1)} at the standard 100/40/30/10/5 paytable with eight decks. Reduced paytables push it well past 5%.
Is 21+3 better than Perfect Pairs?
At full paytables they are close — roughly 3.7% versus 4.1% — and 21+3 wins slightly more often, which makes it feel friendlier. Both remain many times the cost of the main game.