A moulded bra has smooth, seamless cups made from a single piece of fabric. The cups are shaped using heat so they gently follow the natural form of your bust. Moulded does not mean padded – the cups can be thin and soft, giving a natural, flexible fit.
A padded bra has extra material inside the cups. The padding helps the cups keep their shape at all times – even when the bra is in your drawer. Unlike moulded cups, padded ones do not adapt to your body, but hold their pre-shaped form, which can be useful if your bust size differs between sides.
Simply put:
Moulded = shaped to you.
Padded = keeps its shape.