it is more correct to compare with the height:
(Unit：CM)
90=2T：length=38 bust=36 shoulder=29 sleeve=35, fits for: 75-85cm height / 2 Years Old

100=3T：length=41 bust=38 shoulder=30 sleeve=38, fits for: 85-95cm height / 3 Years Old

110=4T：length=44 bust=40 shoulder=31 sleeve=41, fits for: 95-105cm height / 4 Years Old

120=5T：length=47 bust=41 shoulder=32 sleeve=46, fits for: 105-115cm height / 5 Years Old

130=6T：length=50 bust=43 shoulder=33 sleeve=48, fits for: 115-125cm height / 6 Years Old

140=7T：length=53 bust=45 shoulder=34 sleeve=52, fits for: 125-135cm height / 7 Years Old

150=8T-9T：length=56 bust=47 shoulder=36 sleeve=55, fits for: 135-145cm height / 8-9 Years Old

160=10T-11T：length=58 bust=49 shoulder=37 sleeve=59, fits for: 145-155cm height / 10-11 Years Old

170=12T-13T：length=61 bust=51 shoulder=38 sleeve=62, fits for: 155-160cm height / 12-13 Years Old
Note:
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=2.540cm
3.Please check the figures carefully and order the right size, don't completely depend on the " age advice". It's just for reference.