Typically, variations of traditional games in casinos offer worse odds. This is not the case with Spanish 21. The house edge in Spanish 21 is roughly 0.40%. With respect to blackjack, the house edge can vary from approximately 0.20% to over 1.40%.

The removal of the four tens in each deck gives roughly a 2% advantage to the dealer. The liberal rules of Spanish 21, though, do compensate for this. With optimal play, the house edge of a Spanish 21 table is lower than that of a blackjack table with the same rules on hitting or standing on soft 17.