40G Bra Size — Complete Fit Guide

Measurements for a 40G Bra

To wear a 40G bra comfortably, your body measurements should fall in this range:

40G Sister Sizes

Sister sizes share the same cup volume but use a different band measurement. They are the most useful "Plan B" when your usual size is not in stock or fits slightly off.

• 42A — sister size up: the band is two inches larger and the cup letter drops one. Try this if your 40G band feels too tight.
• 38H — sister size down: the band is two inches smaller and the cup letter goes up. Try this if your 40G band rides up the back.

40G International Size Conversions

How a 40G Bra Should Fit

The most common fit issues for 40G are an over-stretched band and cups that gap or overflow. Use this five-point check every time you try on a new 40G bra:

1. The band sits horizontally across your back at the same height as the front.
2. You can fit two fingers — but not more — flat between the band and your back.
3. The centre gore (front piece between the cups) sits flat against your sternum.
4. The cup encloses your breast tissue with no gap at the top and no spillage at the sides.
5. The straps support the bust without digging into your shoulders.

Best Bra Brands for 40G

Full-bust brands like Panache, Freya, Curvy Kate, Bravissimo, and Wacoal carry 40G with proper engineering for larger cups. Avoid generic department-store brands at this cup size — they almost always under-build.

Common Issues with 40G Bras

• Cup gaps at the top: the cup is too big — sister-size to 38H.
• Spillage over the cup: the cup is too small — sister-size to 42A or up one cup at the same band.
• Band rides up the back: the band is too loose — go down to 38-band with the cup up one letter.
• Wires sit on breast tissue: the cup is too narrow — try a different brand or full-cup style.