40J Bras

40J pairs a 40-inch band with a J cup, which works out at about a 13-inch gap between underbust and bust. Sizing varies more between brands than most people expect, which is why two bras both marked 40J can fit quite differently.

How a 40J should fit

A 40J is a full-bust size, and the engineering matters more than the label. Wide side wings, a firm band with four hooks and seamed cups will outperform a prettier bra with thin straps every time.

Sister sizes to try if 40J isn't right

• Band feels loose but the cup is right — try 38JJ
• Band is comfortable but you're spilling over — go up to 40JJ
• Band digs in — 42HH gives the same cup volume with more room

Best 40J styles

Look for side support panels, which push tissue forward and stop it migrating under the arm — the single most useful feature at 40J. Full cup and balconette shapes both work; strapless is harder at this size and worth trying with a longline style, which spreads the weight across a wider band.