Girls size 4Y is a children's clothing size for girls, typically between the ages of 7 and 10. It is sometimes referred to as an extra small or XS size. The measurements associated with this particular size vary depending on the manufacturer, but generally speaking it will fit a girl who has chest, waist and hip measurements in the range of 24-25 inches (61-64 cm). Girls size 4Y usually corresponds to a US dress size 6 or 8, although some manufacturers may offer sizes that are slightly larger than these two sizes.