A black bra under dark clothes
Short answer: Under dark clothes black is the obvious choice, because the contrast with the fabric is smallest. Under thin black fabric a nude one can still be less visible.
Contrast with the fabric
Under a dark, dense fabric black does not show. That is the simple rule most people use.
The exception
Under a very thin black fabric the outline of a black bra can still show, while a nude one disappears into the shadows.
Black fades
Black underwear fades from heat. Wash in a laundry bag at 40 degrees and avoid the tumble dryer. See the washing guide.
Two colours cover most of it
A black and a nude bra cover almost the whole wardrobe. See bamboo bra without underwire.
Knickers in the same colour
The same principle applies to knickers. See black knickers.
Underwear sets
A set in the same colour looks coherent if something does show. See bamboo underwear for women.
Size
Measure under and across the bust. See the size guide.
Frequently asked questions
Which bra under black clothes?
Black. The contrast with the fabric is smallest.
When is nude better?
Under very thin black fabric, where the outline can show.
How many colours do you need?
Two. A black and a nude cover almost the whole wardrobe.