...
Stockbyte/Stockbyte/Getty Images

A fit model who is usually a size 8 or 10, is traditionally used to determine women's clothing sizes. Then each size up or down is measured by an inch larger or smaller. But in the last few decades, bodies have changed, particularly in the U.S., and needs for new size categories like petite and women’s sizes have arisen. What size you wear depends upon your proportions and the brand, because not all brands use the same measurements.

16 Misses

This is the traditional size 16, which is 3 inches larger than the fit model of a size 10. The sleeve length and bust are proportionate to the size 10 model. Many times a woman will fit almost perfectly into a 16 but the bust is too small, or the seat or waist is tight.

16W Women's

This size takes the standard misses and gives a little extra room in all the measurement areas. The waist, bust and seat are looser and larger by anywhere from a few centimeters to a few inches. A woman has to try clothes on and get to know the brands' sizing styles to know which size to buy.

16 Petite

Petite sizes move down a few inches or centimeters so that a woman who is short, or who has shorter arms or a smaller bust, will get the best fit.

Your Personal Fit

Even buying the same size from the same manufacturer can leave a woman facing differences in size. Men’s clothes are standard measurements based on inches and vary very little, while women's sizes are determined by the measurements of a size 8 or 10 model who might have a small bust or a large waist. Women have even reported trying on two pairs of pants by the same manufacturer in the same style and same size and finding a difference in fit.