it is more correct to compare with the height:
(Unit:CM)
100=3T:length=80 bust=56, fits for: 90-100cm height / 3 Years Old
110=4T:length=90 bust=60, fits for: 100-110cm height / 4 Years Old
120=5T:length=100 bust=64, fits for: 110-120cm height / 5 Years Old
130=6T:length=110 bust=68, fits for: 120-130cm height / 6 Years Old
140=7T/8T:length=120 bust=72, fits for: 130-140cm height / 7-8 Years Old
150=9T/10T:length=130 bust=76, fits for: 140-145cm height / 9-10 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, dont completely depend on the " age advice". Its just for reference.