Jupiterimages/Pixland/Getty Images

Knowing your size in actual measurements helps when you're making your own clothes or browsing through international clothing abroad or online, where your size twelve may not be called "size twelve" in that country. American ready-made clothing and standard clothing sizes became popularized when the U.S.D.A. conducted a study on women's body sizes and created a reliable size chart based on the study in 1939.


Women's shirts are often sized as extra-small, small, medium, large and extra-large. However, knowing your size-twelve measurements can still help you determine your shirt size in situations where you need clothing altered or you plan to make your own clothing. You can determine your chest measurement by wrapping a tape measure around the fullest part of your bust and you can measure your waist by wrapping a tape measure around your natural waist, which is around the belly button level. Size twelve in shirts is considered extra-large with the chest measured between 40 and 42 inches and the waist measured between 33 and 35 inches.


You will in most cases come across standardized clothing sizes when shopping for women's pants. Ironically this is not the case with men's pant sizes, which are often sold using measurements in inches. If you know your pant size measurements, you can accurately alter or make your own pants or shop for specialty pants that sell how men's pants sell. The waist measurement for a women's size twelve is 30.5 to 31.5 inches. The hip measurement is 40 to 41 inches. The inseam is 29 to 31 inches and the height is five feet and five inches to five feet and ten inches.


Women's dress sizes are also commonly measured using standard sizes rather than exact measurements. A size twelve for a dress has the chest measurement of 38 to 40 inches, a waist of 30.5 to 31.5 inches and the height of five feet and five inches to five feet and ten inches. A size twelve women's dress is a size fourteen in Great Britain and a size forty-two in standard European sizes.

Skirts and Shorts

Skirts and shorts are typically sized in either extra-small, small, medium, large and extra-larges or sized using standard sizing. Measuring for skirts and shorts is not difficult because you only need to know your waist size. A size twelve women's skirt or pair of shorts has the waist measurement of 30.5 to 31.5 inches.