Bra Size Charts and Fitting Guide

1. Calculating Your Band Size

In bra construction, your underbust measurement is not your band size. To find your correct Lux Tenebrae size, you must apply the +4 Rule.

THE +4 RULE: Take your snug underbust measurement in inches and add 4 inches.
So if your underbust measurement is around 28” you’ll be needing a UK size 32 bra, 30” – size 34 band, 32” – size 36 band and so on in 2" increments

2. International Band Conversions

Locate your local band size to find your UK Size for ordering.

Bra Band Size Conversion

Underbust

in inches

Underbust

in cms

UK

Band size

US

Band size

EU

Band size

FR

Band size
28" 70 32 32 70 85
30" 75 34 34 75 90
32" 80 36 36 80 95
34" 85 38 38 85 100
36" 90 40 40 90 105

 

3. International Cup Conversions

Note: UK sizing uses double letters (DD, FF, GG) which are more precise for larger volumes.

Cup Size Conversion
UK USA EU FR
A A A A
B B B B
C C C C
D D D D
DD DD/E E E
E DDD/F F F
EE
F DDDD/G G G
FF DDDDD/H H H
G DDDDDD/I I I
GG J J J
H K K K


Cup sizes are named alphabetically e.g. A, B, C… and relate to the volume of the cup in relation to the band size of the bra. The theory is that if your bust measures 1" larger than your underbust then you are an A cup, but the whole system is imprecise and confusing.  In practice most women have an idea of their cup size and we can use the bras they already have that fit to come up with a very good estimation.

To add to the confusion different countries have different names for the same volume

4. The Lux Fit Standard

Leather is an architectural garment; it does not stretch. To ensure a consistent fit, our patterns are built on these industry standards:

  • Cup Sizes A–D: Patterned on Agent Provocateur.
  • Cup Sizes D–J: Patterned on Curvy Kate.
  • The "Pain Rule": Leather has zero "give." If you are between sizes, Size Up. Our bras include a powermesh back and triple-clasp closure for 1" of leeway, but a bra that is too tight will be painful.

5. The "Black First" Strategy

Because coloured leathers are Non-Returnable, we strongly advise all new clients to order their first bra in Black Leather.

This establishes your "Lux Size." If the black version isn't perfect, we will exchange it and use your feedback to hand-make a replacement. Once your size is locked in, you can order bespoke colours with total confidence.