Sizing Information Page

Bras

Because there is no sizing standard for bras, bra pattern sizing will differ from company to company. To further complicate matters, there is no one measurement method to determine what size will work for every body (including the one on our pattern envelope).

The only reliable way to determine bra size is to try on finished bras made from that pattern. Given the bra sizing challenge, we recommend starting by making your ready-to-wear size.

We always recommend making a muslin first to test the fit of the bra. This applies not only to new patterns but also to any new fabric you decide to use. We have two tutorials showing you how to make muslins (a.k.a. toiles), a fast way and a more thorough way.

If you do not have a ready-to-wear size or at a loss for what size to start with, we offer the below sizing guidelines for our bra sewing patterns. If you have any sizing questions, feel free to contact us! 

SISTER SIZES

Sister sizes are bra sizes that have the same bra cup volume and underwire size. The difference between sister sizes is the size of the band. For example, the sizes 30D, 32C, 34B and 36A all have the same cup volume and use the same underwire. The difference between those sizes is the band. This blog post has instructions for how to modify the band to reach the sister sizes on this table.

WIRE	BRA SIZE
28	30A
30	30B	32A
32	30C	32B	34A
34	30D	32C	34B	36A
36	30DD	32D	34C	36B	38A
38	30DDD	32DD	34D	36C	38B	40A
40	30G	32DDD	34DD	36D	38C	40B	42A
42	30H	32G	34DDD	36DD	38D	40C	42B	44A
44	30I	32H	34G	36DDD	38DD	40D	42C	44B	46A
46	30J	32I	34H	36G	38DDD	40DD	42D	44C	46B	48A
48		32J	34I	36H	38G	40DDD	42DD	44D	46C	48B
50			34J	36I	38H	40G	42DDD	44DD	46D	48C
52				36J	38I	40H	42G	44DDD	46DD	48D
54					38J	40I	42H	44G	46DDD	48DD
56						40J	42I	44H	46G	48DDD

Note: Only the Marlborough, Boylston and Devonshire bras cover the entire range. The remainder of the bra patterns extend from A to DD only.

INTERNATIONAL CUP SIZE CONVERSION

USA	UK	France, Spain, Belgium	Italy, Czech Republic	EU, Japan	Australia, New Zealand
AA	AA	AA	---	AA	---
A	A	A	A	A	A
B	B	B	B	B	B
C	C	C	C	C	C
D	D	D	D	D	D
DD or E	DD	E	DD	E	DD
DDD or F	E	F	E	F	E
DDDD or G	F	G	F	G	F
DDDDD or H	FF	H	FF	H	FF
I	G	I	G	I	G
J	GG	J	GG	J	GG

INTERNATIONAL BAND SIZE CONVERSION

USA	UK	France, Spain, Belgium	Italy, Czech Republic	EU, Japan	Australia, New Zealand
30	30	80	0	65	8
32	32	85	1	70	10
34	34	90	2	75	12
36	36	95	3	80	14
38	38	100	4	85	16
40	40	105	5	90	18
42	42	110	6	95	20
44	44	115	7	100	22
46	46	120	8	105	24
48	48	125	9	110	26
50	50	130	10	115	28

Underwear

Underwear patterns are based on a waist and hip measurement.

Garments

Garment patterns are based on bust, waist and hip measurements.