it is more correct to compare with the height:Unit：CM70=3M-6M：full length=56 bust=54 sleeve=29, fits for: 65-70m height / 6-9 Months80=6M-12M：full length=59 bust=56 sleeve=31, fits for: 70-80cm height / 9-12 Months90=12M-18M：full length=62 bust=58 sleeve=33, fits for: 80-85cm height / 12-18 Months95=18M-24M：full length=65 bust=60 sleeve=35, fits for: 85-90cm height / 18-24 MonthsNote: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.