👙 Bra Size
40K Bra Size — UK, EU & French Conversion
A US 40K bra in UK, European and French sizing, with its sister sizes. Not sure 40K is right? Measure with the bra calculator first.
US 40K = UK 40H
EU 90K · French 105K
A US 40K bra converts to UK 40H, EU 90K and French 105K. The band number maps on a fixed scale, while cup letters shift between systems above D.
| Region | Size |
|---|---|
| US | 40K |
| UK | 40H |
| EU (Europe) | 90K |
| FR / ES (France, Spain) | 105K |
Sister sizes for 40K
Same cup volume, different band — try these if the band feels tight or loose but the cup is right:
42JSister up
⚠️ US cup lettering above D varies by brand (DD vs E, DDD vs F). Match by the EU/UK equivalent when a brand's letters differ.
All bra sizes → · Bra calculator → · Converter →
What is a US 40K bra in UK and EU sizing?
A US 40K is a UK 40H, EU 90K and French 105K.
What are the sister sizes of 40K?
Same cup volume, different band: 42J.
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