It is more correct to compare with the height:
(Unit:CM)
120=5T:Length=66 Bust=94 Shoulder=40, fits for: 105-115cm height / 5 Years Old
130=6T:Length=70 Bust=98 Shoulder=41, fits for: 115-125cm height / 6 Years Old
140=7T:Length=74 Bust=102 Shoulder=42, fits for: 125-135cm height / 7 Years Old
150=8T-9T:Length=78 Bust=106 Shoulder=43, fits for: 135-145cm height / 8-9 Years Old
160=10T-11T:Length=82 Bust=110 Shoulder=44, fits for: 145-155cm height / 10-11 Years Old
170=12T-13T:Length=86 Bust=114 Shoulder=45, 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.