A 4C shoe size is generally a 2.5-inch shoe size. A lot of retailers stop at the next whole (3 inches) size when it comes to children's shoes, so this would be a half-size above that. When buying children's shoes, you will want to measure their feet and make sure they have not bunched toes or put their index finger in-between their heel and the end of the shoe. Some notes: Most retail stores have sizes listed on their children's shoe racks. A majority of the time, they are listed in whole numbers or fractions, such as 2.5 or 2/1. You will want to measure your child's foot and round up to the next whole size when measuring your child's foot.