it is more correct to compare with the height:Unit: CM(XS)=5T/6T：length=55.5 bust=83.5 shoulder=35.5 sleeve=51.5(S)=7T/8T：length=56.5 bust=89.5 shoulder=36.5 sleeve=54.5(M)=9T/10T：length=58.5 bust=92.5 shoulder=37.5 sleeve=56.5(L)=11T/12T：length=60.5 bust=95.5 shoulder=38.5 sleeve=58.5(XL)=13T/14T：length=62.5 bust=98.5 shoulder=39.5 sleeve=60.5size: XSfits for: 115-120cm height / 5-6 Years Oldsize: Sfits for: 125-130cm height / 7-8 Years Oldsize: Mfits for: 135-140cm height / 9-10 Years Old size: Lfits for: 145-150cm height /11-12 Years Oldsize: XLfits for: 155-160cm height /13-14 Years OldNote:1.There is 2-3% difference according to manual measurement.(1 inch = 2.54 cm)2.All measurement in cm, please note 1cm=0.3937ch, 1 inch=2.540cm3.Please check the figures carefully and order the right size, don't completely depend on the " age advice". It's just for reference.