*Evolution Gaming 8-deck with 100:1/40:1/30:1/10:1/5:1 paytable. House edge rises significantly with fewer decks or lower payouts. Sources: Wizard of Odds, PlayUSA, LeoVegas.
I'll be honest: I resisted 21+3 for years. "A side bet is a side bet," I told myself. "They're all just ways to lose money faster." Then I sat at an Evolution Gaming live dealer table with a friend who was betting 21+3 on every hand. Two hours in, he hit a straight flush — 40:1. On a $10 bet. His $400 return covered the entire side bet cost of the session plus a profit.
That didn't make 21+3 a "good bet" mathematically. The house edge is real and substantial compared to the main game. But it changed how I thought about it. The straight flush felt genuinely exciting in a way that a winning blackjack hand simply doesn't. The occasional 100:1 suited trips win is electric. If you're going to play any side bet at all, understanding exactly how 21+3 works — and which tables offer the best version — is worth knowing.
The 21+3 side bet was introduced in Las Vegas in 2001 and has since become the most widely offered blackjack side bet in both land-based and online casinos worldwide. Its mechanics are borrowed directly from Three-Card Poker — a game that combines well with blackjack because both involve rapid decisions on initial two-card hands.
The bet's appeal: five different winning conditions instead of one, payouts ranging from 5:1 to 100:1, and a house edge that — while much higher than the main blackjack game — is lower than most competing side bets. Our broader blackjack side bets guide ranks it as the best-value side bet available at most tables.
What is the 21+3 Side Bet?
The 21+3 side bet is an optional wager available before each deal at participating blackjack tables. The "21" refers to the blackjack game, and the "+3" refers to the three cards used to evaluate the bet: your first two cards plus the dealer's upcard.
If those three cards form any of five qualifying poker hands — flush, straight, three of a kind, straight flush, or suited three of a kind — you win according to the table's paytable. The result has no connection to your blackjack hand outcome. You can win 21+3 on a hand you ultimately lose to the dealer, or lose 21+3 on a hand where you get a blackjack.
21+3 uses the exact same hand rankings as Three-Card Poker — a popular standalone casino game where players also form the best three-card hand. The main differences: in Three-Card Poker you choose one of your cards + dealer's hand, while in 21+3 it's always your first two cards and the dealer's upcard specifically. Players who already know Three-Card Poker will find 21+3's hand rankings immediately intuitive.
How 21+3 Works — Step by Step
- Before the deal: Place your main blackjack bet in the main circle. Then place your 21+3 bet in the marked "21+3" circle (usually adjacent to the main bet area). Minimum side bet is typically $1 at most tables.
- Cards are dealt: You receive two face-up cards. The dealer receives one face-up card (the upcard) and one face-down card (the hole card).
- 21+3 resolved immediately: Before you make any blackjack decisions (hit, stand, double, split), the three-card combination — your two cards + dealer upcard — is evaluated. If it qualifies, you're paid immediately. If not, your side bet is collected.
- Blackjack hand continues normally: The side bet result doesn't affect how you play your main hand. Use standard basic strategy for all main game decisions regardless of whether you won or lost 21+3.
One mistake players make: they adjust their blackjack decisions based on 21+3 results. If you win 100:1 on 21+3, you might be tempted to play your main hand more conservatively to "protect" the win. Don't. The main game and side bet are completely independent. Always play your blackjack hand according to the correct strategy regardless of what happened on 21+3. Mixing the two up is how side bet wins get eroded by main game mistakes.
All 5 Winning Hands — Payouts & Probabilities
All five winning combinations are ranked identically to Three-Card Poker. Here they are from most common to rarest:
| Hand | Description | Payout (Standard) | Prob 6-deck | Prob 8-deck |
|---|---|---|---|---|
| Flush | 3 same-suit cards | 5:1 | ~4.96% | ~4.96% |
| Straight | 3 consecutive ranks | 10:1 | ~3.26% | ~3.26% |
| Three of a Kind | Same rank, diff suits | 30:1 | ~0.22% | ~0.22% |
| Straight Flush | Consecutive + same suit | 40:1 | ~0.22% | ~0.22% |
| Suited Three of a Kind | Same rank + same suit | 100:1 | ~0.06% | ~0.06% |
| No qualifying hand | — | Lose | ~91.28% | ~91.28% |
The overall win probability hovers around 8.72% — roughly 1 in 11.5 hands produces any qualifying combination. Most of those wins will be flushes (5:1) or straights (10:1). The three-of-a-kind, straight flush, and suited-trips outcomes are rare enough to feel like genuine jackpot moments when they land.
House Edge by Deck Count & Paytable
The 21+3 house edge is highly sensitive to two variables: number of decks in the shoe, and the specific payout table being used. Fewer decks increase the probability of repeated ranks (improving three-of-a-kind odds) but can also shift flush probabilities. Here's the full breakdown:
| Decks | House Edge (Standard Paytable) | RTP | Notes |
|---|---|---|---|
| 1 deck | ~13.39% | 86.61% | Avoid entirely — some online RNG versions |
| 4 decks | ~6.39–8.78% | 91.22–93.61% | Worse than 6/8-deck despite fewer decks |
| 6 decks | ~3.7–4.14% | 95.86–96.3% | Most common land-based offering |
| 8 decks BEST | ~3.62% | 96.38% | Best house edge; most Evolution live tables |
The paytable structure matters as much as the deck count. The original 1990s-era 21+3 paid a flat 9:1 for all winning hands — no differentiation between a flush and a suited three of a kind. This flat paytable still appears at some older land-based venues and carries a much higher house edge. Always check the posted paytable before betting.
| Paytable Version | Suited Trips | Straight Flush | Three of a Kind | Straight | Flush | House Edge (6-deck) |
|---|---|---|---|---|---|---|
| Evolution Standard BEST | 100:1 | 40:1 | 30:1 | 10:1 | 5:1 | ~3.7% |
| Playtech Standard | 100:1 | 40:1 | 30:1 | 10:1 | 5:1 | ~3.7% |
| Ezugi Variant | 100:1 | 40:1 | 25:1 | 10:1 | 5:1 | ~4.1% |
| IGT Version | 100:1 | 35:1 | 25:1 | 10:1 | 5:1 | ~4.5% |
| 21+3 Xtreme WORST | 30:1 | 20:1 | 10:1 | 5:1 | 3:1 | ~13.4% |
| Flat Rate (legacy) | 9:1 | 9:1 | 9:1 | 9:1 | 9:1 | Very high |
The "Xtreme" variant of 21+3 dramatically cuts payouts — suited three of a kind drops from 100:1 to 30:1, straight flush from 40:1 to 20:1, and three of a kind from 30:1 to 10:1. This version carries a house edge of approximately 13.39% in a 6-deck game — nearly four times worse than the standard version. It's been offered at some Las Vegas Strip Party Pit tables. If you see "21+3 Xtreme" on the felt, walk away. The standard payouts (100/40/30/10/5) are printed right on the table felt — spend five seconds verifying before betting.
Provider Comparison: Who Offers the Best 21+3?
Best choice: Evolution Gaming 8-deck tables, where the 3.62% house edge is the lowest available for this bet. Playtech's 6-deck implementation (3.7%) is the next best option. Avoid any version with the Xtreme paytable or any flat-rate paytable below 30:1 for three of a kind.
Can You Count Cards on 21+3?
This is a question serious players ask — and the honest answer is: technically yes, but practically very difficult.
Standard card counting systems (Hi-Lo, KO, Omega II) track the ratio of high to low ranked cards remaining in the shoe. They tell you nothing about suit composition. Since flush probability in 21+3 depends on suit density — not just rank — a standard count is only partially relevant.
Some researchers have explored specialized side-card counting approaches that track suits. These can theoretically shift the flush probability in your favor at specific count thresholds. However, the practical challenges are significant:
- You'd need to simultaneously run a standard count for main-game decisions and a suit-tracking count for 21+3
- With 6–8 decks in play, suit concentration shifts very slowly — creating large swings requires significant depletion of one suit
- Most live casinos now use automatic shufflers that reduce penetration, limiting counting windows
The conclusion: 21+3 is not practically countable for most players. This contrasts with Insurance, which has a clear, simple, verified count trigger (True Count +3 in Hi-Lo). If you're going to invest time in card counting skills, the main game and Insurance counting offer far better expected return on that effort. Our complete card counting guide covers the standard and specialized counts in detail.
Is 21+3 Worth Playing?
I play 21+3 occasionally when I'm in a session where I want more action without increasing my main bet. The key word is occasionally. A $2 21+3 bet on every hand over 200 hands at 4% house edge costs me an expected $16 extra. That's my price for the excitement of watching the three-card combination resolve every hand. Whether that's worth it is genuinely a personal decision — but make sure you know what you're paying for entertainment before you sit down.
Here's the framing that makes the most sense:
- 21+3 is the best-value side bet at most blackjack tables. If you're going to play any side bet, 21+3 at 3.62–4.14% is significantly better than Perfect Pairs (~5%), Insurance (~7.4%), or Lucky Ladies (~17–25%).
- But it's still 7–12�— worse than the main game. The main game with basic strategy runs at ~0.35–0.5% edge. You're paying a real and meaningful premium per dollar for 21+3.
- Keep it small. Cap your 21+3 bets at 10–20% of your main bet size. $10 main bet → $1–2 21+3. This way the side bet adds excitement without meaningfully distorting your session's mathematical outcome.
- Choose the right table. The difference between Evolution's 3.62% and IGT's 4.5% is real over hundreds of hands. Seek out 8-deck tables with the 100/40/30/10/5 paytable when possible.
If you're playing 200 hands at $10 main bet, your session wager on the main game is $2,000. A $2 21+3 bet every hand adds $400 in side bet wagering. At 4% house edge, that's an expected $16 in extra losses from side bets — roughly one moderately good main-game hand's worth. That's a reasonable entertainment premium if 21+3 makes the session more engaging for you. A $5 21+3 bet would cost an expected $40 in side bet losses — at that point it dominates your session math significantly. Our bankroll management guide has frameworks for budgeting side bets into session planning.
21+3 vs Other Side Bets
| Side Bet | House Edge | Max Payout | Win Frequency | Best For |
|---|---|---|---|---|
| 21+3 (standard) | ~3.62–4.14% | 100:1 | ~8.7% | Most players — best balance of edge and excitement |
| Perfect Pairs | ~2.2–11% | 30:1 | ~7.5–13% | Players wanting simpler win condition |
| Hot 3 | ~2.5–6.4% | 100:1 | ~17% | Players wanting more frequent small wins |
| Royal Match | ~3.7–6.7% | 25:1 | ~24% | Players wanting high frequency, lower max |
| Insurance | ~7.4% | 2:1 | Only when dealer shows Ace | Card counters only (TC +3) |
| Lucky Ladies | ~17–25% | 1,000:1 | ~15% | Jackpot chasers — not recommended |
21+3 sits in a sweet spot: low enough house edge to be the most defensible side bet choice, high enough max payout (100:1) to deliver genuinely exciting moments, and frequent enough wins (~1 in 11.5 hands) to stay engaging across a session. The alternative worth considering is Hot 3 if you want more frequent small wins and accept a comparable house edge.
For a comprehensive view of all side bets including ones not listed here, our complete blackjack side bets hub covers 8 bets with full analysis.
Frequently Asked Questions
What is the 21+3 side bet in blackjack?
21+3 is an optional side bet that uses your first two cards plus the dealer's upcard to form a three-card poker hand. You win if those three cards create a flush (5:1), straight (10:1), three of a kind (30:1), straight flush (40:1), or suited three of a kind (100:1). The bet is resolved before any main-game decisions and is completely independent of your blackjack hand outcome.
What does 21+3 pay?
Standard modern paytable (Evolution Gaming, Playtech): Flush = 5:1 · Straight = 10:1 · Three of a Kind = 30:1 · Straight Flush = 40:1 · Suited Three of a Kind = 100:1. Older or reduced paytables pay less — specifically watch for the "21+3 Xtreme" version which caps suited trips at 30:1 and carries a house edge of ~13.4%. Always verify the posted paytable before betting.
What is the house edge for 21+3?
With the standard paytable: approximately 3.62% (8-deck Evolution Gaming), 3.7% (6-deck standard), and rising to 6.39–8.78% in 4-deck games and 13.39% in single-deck games. More decks = lower house edge for 21+3. Always prefer 8-deck tables when available, and confirm the 100/40/30/10/5 paytable structure before playing.
How often do you win the 21+3 side bet?
The overall probability of any qualifying hand is approximately 8.72% — roughly 1 in every 11–12 hands. The most common wins are flushes (~4.96%) and straights (~3.26%). Three of a kind and straight flushes each occur around 0.22% of the time. Suited three of a kind — the 100:1 jackpot — hits approximately 0.06% of the time, or roughly once every 1,600 hands.
Is 21+3 the best blackjack side bet?
In terms of house edge, yes — 21+3 with the standard paytable (3.62–4.14%) is the best-value widely available blackjack side bet. It's significantly better than Perfect Pairs (2.2–11% with high variation), Royal Match (3.7–6.7%), Insurance (7.4%), and Lucky Ladies (17–25%). Hot 3 is comparable at 2.5–6.4% depending on the venue. No side bet approaches the main game's 0.35–0.5% house edge with basic strategy.
Can you use card counting on the 21+3 side bet?
Theoretically possible but practically very difficult. Standard card counts don't track suit composition, which is essential for 21+3's flush probability. Specialized suit-tracking counts can theoretically shift flush odds, but require simultaneously maintaining both a main-game count and a suit count — extremely complex in a live table environment. With 6–8 decks and modern shuffling procedures, count-driven advantages on 21+3 are marginal. Unlike Insurance (clear and verified at TC +3), 21+3 counting is not practical for most players.
📚 Sources References
- Wizard of Odds — "21+3" (dedicated page): Complete return table by deck count, 21+3 Xtreme paytable analysis, progressive version edge, original 9:1 flat paytable data. wizardofodds.com/games/blackjack/side-bets/21plus3
- PlayUSA — "21+3 Blackjack Side Bet" (June 2025): 8-deck house edge 3.62%, 6-deck 3.7%, 4-deck 6.39%, single-deck 13.39%. Las Vegas venue availability (MGM, Caesars, M Resort, Rampart). Evolution vs IGT paytable comparison. playusa.com
- LeoVegas — "21+3 Blackjack Side Bet: Complete Guide": Favorable paytable house edge ~2.74%, overall win probability breakdown, 6-deck vs 8-deck probability differences. leovegas.com
- LiveCasinoComparer — "21+3 and Perfect Pairs Explained" (April 2026): Provider-by-provider paytable comparison — Evolution, Playtech, Ezugi, Pragmatic Play, LuckyStreak, Visionary iGaming payout structures. livecasinocomparer.com
- ReadWrite — "21+3 Blackjack Side Bet: Rules, Payouts, Odds & Strategy" (July 2025): 6-deck house edge 4.14%, 8-deck 3.18%, Lucky Ladies comparison, card counting impracticality for 21+3. readwrite.com
- PokerNews — "Blackjack Side Bets: Odds, House Advantage & Payouts Guide" (October 2025): 21+3 house edge by deck count table (4-deck 8.78%, 5-deck 7.81%, 6-deck 7.14%, 7-deck 6.29%), side bet introduction overview. pokernews.com
- DotEsports — "Blackjack Side Bets: Payouts, Odds & How They Work" (December 2025): Evolution/Pragmatic paytable verification, suited three of a kind 100:1 confirmation, three-card poker hand structure. dotesports.com
- Winstar World Casino — "Odds in Blackjack": Live casino 21+3 paytable confirmation (100:1 suited trips), house edge 3–7% range corroboration. winstar.com