Are you, like most women, using the try on until one fits method when you shop for bras?


The following information should help make determining your bra size easier. However, because bust shapes, bust positions on the body, and bra styling vary, the precise bra size cannot be determined without a fitting. 

© Grading to Fit, ISBN 0-966323-4-5,  Laurel Hoffmann, 2009.
Bra companies determine a woman’s bra size by first measuring the chest under the bust, then adding five inches to give the bra size’s circumference measurement. If the bust measures the chest size plus 5 inches, the cup size is a C, the average cup size in each bra size.
For example: A woman with a 31 inch chest adds 5 inches to determine that she wears a bra with a 36 inch circumference. If her bust measures 36 inches she wears a C cup. If her bust measures one inch less – 35 inches, she wears a B cup; one inch more – 37 inches, a D cup.

© Grading to Fit, ISBN 0-966323-4-5,  Laurel Hoffmann, 2009.


The cup size is directly related to the chest circumference. As shown in the above chart, the same cup size is given a smaller name if it is used with the next larger chest circumference. If a 36 bra’s C cup size fits well, but the bra’s circumference is a bit loose, it might be better to try a 34 bra with a D cup size as the D cup in the size 34 bra is the same size as the C cup in the 36 size bra.
The commercial (home sewing) pattern companies use the same system, but traditionally draft their patterns with a B cup. Their sizing charts give a bust measurement two inches larger than the chest measurement – which would be an AA cup size, but because the pattern’s actual bust measurement is four inches more than the chest measurement the pattern’s true cup size is a B. Confusing, but I guess they’ve done it that way for so long changing the measurements on the pattern packet would be even more confusing.
The pattern companies also say that pattern sizing should be determined by the bust size. But unless you are a B cup this doesn’t work. One’s pattern size is better determined by the chest size, measured under the chest. Then, if extra room is needed over the bust that amount needs to be drafted in.
If the bust is smaller than a B cut, the difference needs to be removed. If you are large busted choosing your pattern size by your bust measurement puts half the extra bust measurement in the back of your pattern. It also throws off all the other pattern’s measurements. So you wind up with a pattern that is too big all over. If you are small busted the pattern may fit the bust, but the pattern is too small everywhere else.


If you’ve read down to here, thank you! Here is a little present, the link to the Great BritishSewingBee.

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