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125D bra size

A 125D bra is cut for an underbust of 122.5–127.5 cm and a bust of 143–145 cm. Below it is the same size as every other system prints it, and the sister sizes that hold the same cup.

125D in every system

EU
125D
RU
125D
US
54D
UK
54D
FR
140D
IT
12D
JP
125D

Where each notation comes from

What each notation means — why the British band reads 34 and the Italian reads 2 — is set out system by system on the bra size page.

Sources

Nothing here is looked up in a table of equivalents: band and cup are computed once from the metric ladder, then printed in each system’s own letters (formula version 2).

  • en.wikipedia.org the underbust ladder in 5 cm steps and the AA–H cup table
  • en.wikipedia.org the British and American cup runs, the French +15 shift, the Italian numbering
  • en.wikipedia.org the "+0" and "+4" methods, sister sizes, measuring upright and leaning forward
  • ru.wikipedia.org the Russian table: the same intervals, the same letters

Checked: no date on record

Where these numbers come from

The band is the underbust rounded to the nearest five centimeters, so 122.5–127.5 cm all round to 125. The cup is how far the bust exceeds that band’s nominal value: 18–20 cm gives this letter, at two centimeters per letter starting at ten. Add them and you get a bust of 143–145 cm.

The cup is measured against the nominal 125, not against the tape. That is what every published chart does, and it is why an underbust at the bottom of this band and one at the top get the same letter despite five centimeters between them. Near a band edge, try the sister size too.

In inches, 125D is an underbust of 48.2–50.2" and a bust of 56.3–57.1". Note that the UK and US band number is not that measurement: 125 cm is 48.2–50.2", and the band is called 54D because the English notation adds four inches.

Same cup as 125D, different band

One band up is one letter down, because the cup is measured over the band — which makes 120E the same volume as 125D. In a shop the printed size that fits is routinely not the one the tape said, so these are worth trying on.

One step away

120D — a letter either side of 125D on this band, and this letter on the neighbouring bands.