A Royal Flush is an Ace, King, Queen, Jack and Ten, all of one suit. It is the highest hand in the poker hand rankings, and nothing beats it. The only way to share the pot is for someone to hold the same hand.
How it works
All five cards share a suit and form the highest straight there is, 10♠J♠Q♠K♠A♠. It is not a category of its own but the top Straight Flush, which is why some rankings list the two as one line.
The order of the cards does not matter, and neither does the suit: 10♥J♥Q♥K♥A♥ is the same hand as 10♣J♣Q♣K♣A♣. That is where the count comes from: four combinations, one per suit.
Can a royal flush be beaten?
No. There is no higher hand, so a Royal Flush can never lose.
It can be tied in exactly one way: when the five community cards are themselves a Royal Flush. Every player still in the hand then holds it, and the pot is split evenly. A Royal Flush has no kicker, so there is no other way to break it.
Royal flush vs straight flush
Every Royal Flush is a Straight Flush, but almost no Straight Flush is a Royal. A Straight Flush can run in ten sequences, from A-2-3-4-5 up to 10-J-Q-K-A, and the Royal takes one of them.
Hence the gap: four Royal Flushes against 36 other Straight Flushes. A Royal is nine times rarer than the next best hand and 156 times rarer than Four of a Kind.
Probability
There are two ways to count it, and they diverge further here than for any other hand.
- In a five-card deal: 4 combinations out of 2,598,960 - that is 0.000154%, or 1 in 649,740.
- In seven-card Hold’em: 4,324 out of 133,784,560 - that is 0.0032%, or about 1 in 30,940.
Both numbers come out in one line:
- five-card: 4 suits x 1 sequence = 4;
- seven-card: 4 Royal Flushes x 1,081 pairs of leftover cards = 4,324.
The second number is the one that means anything at the table. Out of seven cards a Royal Flush lands 21 times more often than out of five, and it is still the rarest hand in poker.