The size 10-12/M in LLBean is closest to the following:
Brand Label Weight (lbs) Height (inches)
American Apparel 12 years 62 - 75 lbs 55 - 59 inches
Burt's Bees Baby (Target) 7 53 lbs 48 - 51.5 inches
Cherokee (Target) 7 48.5 - 54 lbs 47 - 48.5 inches
Circo (Target) 7 48.5 - 54 lbs 47 - 48.5 inches
H&M 7-8 years - 50 inches
Hanna Andersson 140cm 62 - 80 lbs 54 - 58 inches
Hatley 10 - 56 inches
J.Crew/ Crewcuts 10 73 - 76 lbs 55 - 56 inches
LLBean 10-12/M - 53 - 58 inches
Lands End 7/L 49 - 54 lbs 47 - 49 inches
Marimekko 10 yrs/140cm - 55 inches
MiniBoden 10y - 55 inches
Petit Bateau 10Y 48 - 53 lbs 54.5 inches
Ralph Lauren 10/ M 63 - 73 lbs 54.5 - 56 inches
The Children's Place 0-3 months 7 - 11 lbs -
janie and jack 6 44 - 52 lbs 52 - 62 inches
tea 10/L 72 - 82 lbs 54 - 57 inches