- 1). Determine personal clothing sizes. School girl costumes are usually based on normal clothing sizes, typically starting at size four.
- 2). Look at the available sizes in the costume. School girl costume sizes are often labeled as extra small, small, medium, large and plus size. The sizing charts often relate to the normal clothing sizes; for example, sizes four to six are extra small. The sizes for school girl uniforms go up to plus sizes, which are usually sizes 14 to 18.
- 3). Go with the larger costume when there are doubts about sizes. According to Costume Zone, costumes usually run smaller rather than larger, so if your size is between two sizes, select the larger costume. For example, an extra small costume is usually a size four to six costume while small is usually six to eight. If the normal dress size is six, pick the small costume rather than the extra small.
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