The European glove sizes are measured in old German inches. A German inch equals 2.7 cm, so for the size of 9 it´s 9 German inches or 24,3 cm.
For children´s sizes the proportion in hand size/finger length differs from the adult sizes, since in proportion children have shorter fingers and wider hands. Therefore, the usual European Children´s sizes are not directly convertible by multiplying with 2.7 like in adult´s sizes.
