Demi means half. A demi cup bra covers roughly half the breast with an angled cut, leaving the upper bust exposed. A t-shirt bra covers more and is moulded smooth to disappear under clothing. The demi is about showing shape; the t-shirt bra is about showing nothing.
"Demi" describes how much the cup covers. "T-shirt" describes what the cup surface is like. That is the whole distinction, and it is why the two words get muddled.
Part of our guide to the 15 types of bras.
What does demi cup mean?
A demi cup covers about half to two-thirds of the breast, cut at an angle rather than straight across. The French demi simply means half.
The angled cut is what separates it from a balconette, which is cut flat and horizontal. A demi slopes, so the shape it creates is rounded and lifted rather than squared.
Straps sit closer together than a balconette's but further apart than a full-cup's — roughly in the standard position.
Demi vs t-shirt bra at a glance
| Demi cup | T-shirt bra | |
|---|---|---|
| Coverage | About half the breast | Most of the breast |
| Cup edge | Angled, visible shape | Rounded, follows the bust |
| Surface | Often seamed or lace | Smooth, moulded, seam-free |
| Under thin fabric | Edge can show | Invisible |
| Best for | Lower necklines, shape | Everyday, fitted clothing |
What is the difference between a demi and a t-shirt bra?
Coverage and surface. A demi covers less and often has a visible seam or lace edge; a t-shirt bra covers more and is smooth.
The practical consequence: under a fine jersey top, a demi's cup edge frequently prints a visible line across the bust where the fabric stops. A t-shirt bra has no edge to print, because the cup is moulded in one piece and tapers to nothing.
A bra can be a smooth moulded demi — in which case it behaves like a t-shirt bra under clothes while covering less.
Which suits a smaller bust?
The demi, often. It lifts and creates a defined shape, and the lower coverage means less chance of the gaping that moulded t-shirt cups sometimes produce on a smaller bust.
If a t-shirt bra wrinkles or gaps at the top of the cup, the cup is too big — try a sister size before concluding the style is wrong. See sister sizes explained.
Which suits a fuller bust?
The t-shirt bra, usually. Half coverage on a fuller bust often means spillage over the cup edge, which is both uncomfortable and visible.
If you like the demi shape and have a fuller bust, look for one with a firm band and a slightly higher cut. See best bras for a bigger bust.
Demi, balconette or plunge — which is which?
All three cover less than a full cup, and they are easy to confuse:
- Demi — angled cut, about half coverage, straps in standard position. Rounded lift.
- Balconette — horizontal cut, wide-set straps. Squared lift, for wide necklines. See the balconette bra.
- Plunge — low centre gore, angled cups. Cleavage, for deep V necklines. See the plunge bra.
For a direct comparison of the last two, see plunge vs balcony bra.
Which should you own?
A t-shirt bra first, every time. It is the one that works under the most clothes. Add a demi when you have lower necklines that a fuller cup would show above, or when you want a more defined shape.
Deeper detail on each: the demi-cup bra and the t-shirt bra explained.
Frequently asked questions
What does demi cup mean?
Demi means half. A demi cup bra covers roughly half to two-thirds of the breast with an angled cut, leaving the upper bust exposed.
What is a demi bra used for?
Lower necklines, and creating a lifted, rounded shape. It covers less than a full cup, so it stays hidden under tops a fuller cup would peek above.
What is the difference between a demi and a t-shirt bra?
A demi covers about half the breast and often has a seamed or lace edge. A t-shirt bra covers more and has a smooth moulded cup designed to be invisible under fitted fabric.
What is the difference between a demi and a balconette?
The cut. A demi is angled and creates a rounded shape; a balconette is cut flat and horizontal with wide-set straps, creating a squared shape.
Is a demi bra good for a bigger bust?
Less so. Half coverage can mean spillage over the cup edge. A full-cup or balconette with a firm band usually suits better.
Does Erblis sell demi bras?
We stock a focused range in 32-34 bands — wireless, convertible push-up and front-clasp. Browse the bras collection, or see our brand comparison for wider ranges.