Free calculator
Bra Size Calculator
Measure snugly under the bust and around the fullest part of the bust while wearing a lightly padded bra. Stand relaxed with the tape level at the back.
How it works
The band is your underbust rounded to the nearest 5 cm (EU sizing, EN 13402). The UK band follows the shop chart: EU 70 = UK 32, EU 75 = UK 34, and so on. The cup comes from the difference between bust and underbust: about 12 cm is A, 14 cm is B, 16 cm is C, and every 2 cm after that is the next cup.
Sister sizes keep the same cup volume: go down a band and up a cup if the band feels loose, or up a band and down a cup if it feels tight.
Frequently asked questions
How often should I re-measure?
Every six months, and after weight change, pregnancy or breastfeeding.
Why do UK and US cups differ above D?
The UK uses double letters (DD, FF), the US often uses DDD and then skips; the conversion here is approximate above DD.
How should a bra fit?
The band should be level, firm and sit on the loosest hook when new. The centre gore should touch your chest and the cups should hold all tissue without spilling.
General estimates for information only. Not medical or professional advice. Nothing you enter is saved or sent to us.
