40F

40F is a bra size used in Western lingerie sizing. In US and many markets, the size combines a band measurement of 40 with a cup size of F. The band number refers to the measurement around the torso under the breasts, while the cup letter indicates the volume of the cup relative to that band. Because sizing systems vary by brand and region, a 40F in one brand may not fit the same as a 40F in another; it is common to consult a brand’s size chart and try multiple options.

Measuring guidance: To determine a band size, measure snugly around the ribcage just under the bust. To estimate cup size, measure the fullest part of the bust and compare this difference to the band measurement. The difference is used to select a cup letter according to the brand’s chart, with larger differences resulting in larger cup letters.

Fit and wear: A properly fitting 40F should have a snug, level band that stays in place around the torso, with cups that fully enclose the breasts without spilling over the top or sides. Straps should provide support without digging in. If there is gaping, spillage, or the band rides up, the size or style may not be correct, and a different cup or band size or a different bra cut may be needed.

Notes: Sizing conventions differ by region and brand, and some brands may not use the same cup-letter progression. The best approach is to use brand-specific charts and, when possible, professional fitting to determine the most accurate fit.