The house edge in American roulette is higher than in European roulette due to the additional pocket on the American wheel, which includes a double zero (00). This extra pocket increases the total number of slots to 38, compared to 37 in European roulette, which has only a single zero. As a result, the house edge in American roulette is typically around 5.26%, while in European roulette, it is approximately 2.7%. This significant difference means that players generally have better odds and a lower house edge when playing European roulette compared to its American counterpart.