it is more correct to compare with the height:
(Unit：CM)
120=5T：Tops length=46 bust=84 shoulder=39 sleeve=15 Pants length=65 waist=45 , fits for: 105-115cm height / 4-5 Years Old
130=6T：Tops length=49 bust=88 shoulder=41 sleeve=16 Pants length=71 waist=47 , fits for: 115-125cm height / 6 Years Old
140=7T-8T：Tops length=52 bust=92 shoulder=43 sleeve=17 Pants length=76 waist=49, fits for: 125-135cm height / 7-8 Years Old
150=9T-10T：Tops length=57bust=96 shoulder=45 sleeve=18 Pants length=82 waist=52, fits for: 135-145cm height / 9-10 Years Old
160=11T-12T：Tops length=60 bust=100 shoulder=47 sleeve=19 Pants length=87 waist=54, fits for: 145-155cm height / 11-12 Years Old
170=13T-14T：Tops length=63 bust=104 shoulder=49 sleeve=20 Pants length=92 waist=57, fits for: 155-160cm height / 13-14 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.
EN 
AR