To get the best fit, place your measuring tape on the child's back neckbone and measure straight down to the crotch area (where the snaps would be).  Then measure around his chest directly under the armpits.  For the longall, measure from the top of a shoulder straight down to the ankle or top of the foot.  Those measurements should match one of the sizes below.  If in doubt about a particular size, please order the next size up.  He will have a little growing room and buttons can always be adjusted for a better fit!

Size   Chest    Back Neck to Crotch    Shoulder to Hem Length (Longall)

6-9M   22"              16"                                            23 1/2"

12M     23"              17"                                            24 1/2-25"

18M     24"              18"                                            26-26 1/4"

2T         25"              18 1/2-19"                             27-27 1/4"

3T         26"              20-20 1/2"                            29 1/2-30"

4T         28"              21"                                            31"

5T         28"              22"                                            32"