Question 1

How do I measure my bra size at home?

Accepted Answer

Measure your band size snugly around your ribcage directly under the bust. Round to the nearest even number. Then measure your bust at the fullest point with a soft tape, keeping it level and not too tight. The difference (bust minus band) determines the cup size.

Question 2

What is a sister size?

Accepted Answer

Sister sizes are equivalent cup volumes on different band sizes. For example, 34C has sister sizes 32D and 36B. If a bra feels tight in the band, go up a band and down a cup. If the band rides up, go down a band and up a cup.

Question 3

Why are bra sizes different in US, UK and EU?

Accepted Answer

US, UK, EU and Japanese systems use different size increments. UK and US cup letters are the same (A, B, C, D, DD, E, F, FF, G...). EU uses cm-based band numbers (65, 70, 75...) instead of inches. Japan uses cm-based band and cup in cm. This calculator converts between all four.