Youth large is equivalent to size 12 to 14 in children. Some brands vary in size slightly so each one may fit differently.
Letters or numbers are typically used to denote pant and shirt sizes. Youth large is sometimes referred to as "L" and universally, this size fits children with 31 to 33-inch chests, 26 to 27.5-inch waists and 55 to 60 inches in height. Youth medium is the same as size 8 to 10 and youth small fits children wearing size 6 to 7. Youth X-large is converted into sizes 16 through 18. Adult sizes are commonly used for sizes larger than youth X-large.