G Cup Bras

The cup letter describes the gap between your bust and band, so it only means something alongside a band number — and G is the size where UK and US labels collide:

• A UK G is a US I, not a US G. UK sizing runs A, B, C, D, DD, E, F, FF, G; US sizing reaches the same volumes in fewer steps, so it labels this one I.
• A US G is actually a UK F. If you have shopped a US brand and a UK brand and the letters disagree, this is why. The brands we carry are British, so a G on the label is a UK G.
• EU sizing calls this volume I too: a UK 34G is an EU 75I.
• The band drives volume: a 28G and a 44G share a letter and hold very different amounts, because every cup is cut in proportion to its band.

Two measurements set your size, and one trick fixes most fit problems:

• Underbust — measure snugly around the ribcage directly beneath the bust, tape level all the way round. This gives your band.
• Bust — measure around the fullest point without compressing. The difference between the two gives the cup.
• Sister sizing — if the cup fits but the band does not, move across: down a band means up a cup, and vice versa. A 34G, a 32GG and a 36FF all hold the same volume.

If you land between two bands, take the smaller one and go up a cup. A slightly firm band stretches into place; a slightly loose one only gets looser, and at G cup that means the straps end up carrying weight they were never designed for. For the full walkthrough, see our guide to measuring your bra size, or convert a size you already own with the bra size converter.

Support at a full bust comes from engineering, not luck. The features that separate a bra that works from one that does not:

• A firm, non-stretch band — it does most of the support work. Snug and level on the loosest hook, so you can tighten it as it stretches.
• Wire that fully encircles the breast — sitting flat on the ribcage behind the breast, never on tissue. Wire on tissue means the cup is too small, not that wires do not suit you.
• Seamed three-part cups — the seams direct the breast up and in. Moulded cups can no longer contain this volume, which is why they are rare at G.
• Higher wings and side-support panels — to anchor the breast at the side and stop it migrating under the arm.
• Wider straps and four or more hooks — to spread load and give a deep, stable back.

This is the one category where getting it wrong has physical consequences. Breast tissue has no muscle to support it, and at G cup unsupported movement during running strains the ligaments permanently.

• Encapsulation is essential — separate moulded cups that hold each breast individually. Compression-only styles that work at smaller cups flatten rather than support and do not control movement at G.
• Best in class combines both — encapsulation for control plus light compression for stability.
• The band should be wider and firmer than your everyday bra, with no stretch through the underband.
• Replace them more often than you think — a sports bra loses meaningful support long before it looks worn.

Browse the full sports bra range and filter to your band.

The G range comes from the full-bust specialists, and they differ in useful ways. Panache is the everyday backbone — seamed three-part cups, firm bands, reliable across the band range. Cleo is the younger, more design-led line from the same house. Freya and Fantasie bring prettier styles with full-bust construction. Sculptresse and Elomi specialise in the wider bands, where G runs deep.

To make a G cup bra last, and it matters here because the construction is more expensive: hand-wash in cool water or use a mesh bag on a delicate cycle, fasten the hooks first so they do not snag, never wring the cups, and lay flat or hang to dry. Heat destroys elastic faster than wear does, so keep them out of the dryer entirely. Rotating three bras rather than wearing one on repeat roughly doubles the life of each.