To find your children's recommended earring post stem size, use a ruler or the sizer provided below. Measure the distance from the center of the earlobe to the neck. Begin from the interior side, facing the neck. If the distance is five-sixteenths of an inch (0.31 inches/8mm) or less, we recommend using our extra -small post. Should the distance measure five-sixteenths of an inch (0.31 inches/8mm) or above, we recommend our standard post size. Our extra small post stems measures a total length of one-third of an inch (0.33 inches/8.5 mm). The standard size measures seven-sixteenths of an inch (0.43 inches /11mm). If your ideal fit falls between two sizes, we recommend choosing the larger size. Please contact Customer Care for questions or to request any custom sizes.