Size 6 is the next size after 5T. Some parents may choose to buy regular size 5 clothing once their child is potty-trained because size 6 is noticeably larger than 5T and might be too big. Its important to note that toddler (T) sizes in the United States are labeled solely by the age when the child is expected to fit into them. Additionally, some stores separate the sizes after 5T into gendered "kid" clothing sections, which can be confusing.