How to play Casino War — and the real odds
Casino War is the card game you already know from the schoolyard, dressed up for the pit: high card wins. It takes about ten seconds to learn and has exactly one decision — which makes it the perfect place to see how a house edge is built out of almost nothing.
The deal
You bet the ante. You and the dealer each get one card (aces are high; suits don't matter). Higher card wins even money; lower card loses. That's the entire base game — and on its own it's an even coin flip.
The one decision: a tie
About 7.40% of the time (a shade under 1 in 13) the two cards match rank. That's a tie, and it's the only choice you ever make in Casino War. You can:
- Go to war. You raise — putting up a second bet equal to your ante. The dealer burns three cards and deals one more to each of you. If your card is higher or equal, you win; if it's lower, you lose.
- Surrender. You give up half your ante and the hand is over.
Why going to war still favors the house
Here's the catch that makes the whole game work for the casino. When you go to war you risk two units (ante + raise), but a win only pays you one: the raise pays even money, while your original ante merely pushes (you get it back, no winnings). Ties in the war go to you, so you win a little more than half of wars — but not nearly enough to cover risking two units to win one. Work it out and the drag is exactly 2.88% of your ante.
Surrendering looks tempting — why double down on a coin flip? — but handing back half your bet on every tie works out worse (3.70%). Going to war is the lesser evil, every time.
The Tie side bet: a trap
Most tables offer a side bet that the first two cards will tie, paying 10 to 1. It sounds generous until you notice a tie happens only 7.40% of the time — about 1 in 13.5. A fair payout would be roughly 12.5 to 1, so that 10:1 hides a punishing 18.65% house edge — around six times the main game. It's the worst bet on the table. Skip it.
The exact odds
Every number below is computed in closed form from the rules — no simulation, no rounding games:
Casino War is the simplest game on the floor — one card each, higher wins. And yet the exact math, below, shows it still tilts to the house. Every figure is closed-form (no simulation) for a 6-deck shoe.
(23 in 311)
(same for the dealer)
What each bet really costs
| Bet / choice | House edge | Verdict |
|---|---|---|
| Go to war (on a tie) | 2.88% | Optimal play |
| Surrender (on a tie) | 3.70% | Costs 0.82% more — never do it |
| Tie side bet (10:1) | 18.65% | Sucker bet — ~6× the main edge |
Why it works out this way
- No tie (about 93% of hands): a coin flip — you win or lose one unit, and it washes out to zero on its own.
- A tie (7.40%): here's the catch. Go to war and you must double your bet, but a win only pays even money on the raise — the original ante just pushes. Win 54%‑ish of wars (ties go to you) for +1 unit; lose the rest for −2 units. That asymmetry is the entire house edge.
- Surrendering hands back half your ante every tie — a flat 3.70% drag, worse than the 2.88% from always warring. So the rule is simple: always go to war, never surrender.
- The Tie bet pays 10:1 but a tie hits only 7.40% of the time — a fair payout would be about 12.5:1. That gap is a brutal 18.65% edge. Skip it.
Does the deck count matter?
A little — more decks means a slightly higher tie chance, so a slightly higher edge. Still tiny either way:
| Decks | Go-to-war house edge |
|---|---|
| 1 | 2.42% |
| 2 | 2.70% |
| 6 | 2.88% |
| 8 | 2.90% |
Bankroll reality
A 2.88% edge is genuinely low — lower than roulette, close to some blackjack. But "low" isn't "none": over a night of fast hands it still grinds. And because ties make you double your bet, your swings are a little wider than a pure coin flip. Bet an amount you can lose, and remember the edge is a long-run certainty — see it emerge for yourself in the Lab.
Ready? Play Casino War free → · or compare it with every other game in the house-edge chart →.