The size 12-18 months in H&M is closest to the following:
Brand Label Weight (lbs) Height (inches)
American Apparel 2 years 31 - 34 lbs 32 - 36 inches
BabyBoden 18-24 months 26.5 - 31 lbs 32.5 - 35.5 inches
Burt's Bees Baby (Target) 24 M 28 lbs 32.5 - 35.5 inches
Carters 24 months 27.5 - 30 lbs 32.5 - 34 inches
Cherokee (Target) 24 months/ 2T 26.5 - 28 lbs 33 - 35.5 inches
Circo (Target) 24 months/ 2T 26.5 - 28 lbs 33 - 35.5 inches
Gap 2T 30 - 33 lbs 33 - 36 inches
Gymboree 2T 30 - 32 lbs 33 - 36 inches
H&M 12-18 months - 34 inches
Hanna Andersson 80cm 20 - 27 lbs 30 - 34 inches
Hatley 2 - 35 inches
J.Crew/ Crewcuts 18-24 months 27 - 30 lbs 32 - 37 inches
Jumping Bean (Kohl's) 24 months 26 - 29 lbs 31 - 33 inches
LLBean 2T - 33 - 34 inches
Lands End 2T 27 - 29 lbs 33 - 35 inches
Marimekko 18 months/ 86 cm - 34 inches
MiniBoden 1.5 years - 32.5 inches
Old Navy 2T 30 - 33 lbs 33 - 36 inches
OshKosh 24 months 27.5 - 30 lbs 32.5 - 34 inches
Petit Bateau 24M 24 - 28 lbs 34 inches
Ralph Lauren 24M 28 - 30 lbs 33.5 - 35.5 inches
The Children's Place 0-3 months 7 - 11 lbs -
Tucker + Tate (Nordstrom) 24M 28 - 30 lbs 33.5 - 35.5 inches
Wal-Mart 24 months/ 2T 26.5 - 30 lbs 32 - 35.5 inches
Zutano 24m 24 - 29 lbs 33 - 35 inches
childhoods 2T 30 - 33 lbs 33 - 36 inches
janie and jack 2T 30 - 33 lbs 33 - 36 inches
june and january 2T 25 - 27 lbs 33 - 35 inches
tea 2/ XS 30 - 33 lbs 33 - 36 inches
vineyard vines 18-24 months 27 - 30 lbs 32 - 35 inches