Girls Sizes At a Glance Clothing sizes for kids are usually based on age, height, and weight However, the best way to find the perfect fit for your daughter is to get accurate measurements of several key areas of her body such as the chest, waist, hip, inseam, and height You may also need to record her neck base and sleeve length measurementsMeasurements we need from you 1 NECK Measure around the neck with one finger included 2 NECK OPENING Measure from the center of the front neck to the top of your bust 3 SHOULDER FRONT Measure straight from the edge of one shoulder to the other at the front 4As an average, a Medium is likely to be a around a size 12 Generally a Small will be an AU 810 and a Large an AU 1416 An Extra Small is likely to be a size 6, with an Extra Large likely to be a size 18 This is all dependent on retailers, dress cut and shape — so we'd always recommend trying a dress on, checking the store's own sizing How to measure dress size for girl