In poker, the probability of each type of 5-card hand can be computed by calculating the proportion of hands of that type among all possible hands. Frequency of 5-card poker · Frequency of 7-card poker · Frequency of 5-card. In hold em, the probability you hit a royal flush by the flop is the same as in draw poker. However, we can compute an upper bound for the Odds of Royal Flush over Straight Flush - Gambling. The probability of a four of a kind in seven cards is , the probability of a straight flush is If x is the probability of a four of a kind and y is.