Most people find our toddler and baby sizes run about one size larger than standard.  For a more fitted look, size down.  See info below.  Youth sizes are typical.  

YOUTH

YS:  20-7/8" length, 15-1/4" width, fits sizes 6-8

YM:  22-1/8" length, 16-1/4" width, fits sizes 10-12

YL:  23-3/8" length, 17-1/4" width, fits sizes 14-16

YXL:  24-3/8" length, 18-1/4" width, fits sizes 18-20

TODDLER

2T:  30 - 33 lbs,  32" - 35" height

3T:  33 - 36 lbs,  35" - 38" height

4T:  36 - 40 lbs,  38" - 40" height

5T:  40 - 45 lbs,  40" - 43" height

BABY

3 - 6 mo:    12 - 16 lbs,  20" - 25" height

6 - 12 mo:   16 - 22 lbs,  25" - 28" height

12 - 18 mo:  22 - 27 lbs,  28" - 30" height

18 - 24 mo:  27 - 30 lbs,  30" - 32" height