The size 12 in janie and jack is closest to the following:
Brand Label Weight (lbs) Height (inches)
H&M 7-8 years - 50 inches
Hanna Andersson 150cm 75 - 95 lbs 58 - 62 inches
Hatley 12 - 59 inches
LLBean 14-16/L - 59 - 63 inches
Marimekko 11 yrs/ 146 cm - 58 inches
MiniBoden 12y - 60 inches
Ralph Lauren 14/L 88 - 101 lbs 59 - 61 inches
janie and jack 12 86 - 98 lbs 58 - 60 inches
tea 12/XL 82 - 95 lbs 57 - 60 inches