PLEASE NOTE: This size chart has been provided by the manufacturer. Figures are based on approximate garment measurements in inches. Chest is measured one inch below the underarm. Outseam is measured from the waist to the ankle. Sleeve is measured shoulder to shoulder straight across the back. Please allow 3-5 inches for fitting on the chest measurements as you have to remember that the boy will have the shirt on, sometime a vest depending on style selected and then the jacket. You must allow for easement so that they can move freely. Additionally, these can be altered just like a mans garment. Check drop down menu for sizes offered as sizes offered are by style and not necessarily offered in all sizes that are listed above.