Bra AtlasBra sizing, measured and sourced

34DD sister size chart, conversions and measurements

34DD was the most common self-reported size in a UK study that compared the traditional method with professional fitting, and that study found the old method oversized bands and undersized cups.

Bra Atlas fitting card

34DDUK · same in the US

Measures about 34 in underbust and 39 in bust. Same cups as 32E and 36D.

UK
34DD
US
34DD
EU
75E
FR
90E
AU
12DD
JP
F75

Same cups 32E34DD36D

Every sister of 34DD

  • 30FTighter band by 4 in, 2 cup letters up (US 30G, EU 65G)
  • 32ETighter band by 2 in, 1 cup letter up (US 32DDD, EU 70F)
  • 34DDThis size (US 34DD, EU 75E)
  • 36DLooser band by 2 in, 1 cup letter down (US 36D, EU 80D)
  • 38CLooser band by 4 in, 2 cup letters down (US 38C, EU 85C)

By Rai Ansar · Sizes computed by the Bra Atlas engine · Sources and checked dates · How the sizes are calculated

32E: band 32 in, same cup volume. Shown: a woman with fair skin, freckles and wavy copper hair in a powder blue bra.

32E

tighter band

34DD: band 34 in, same cup volume. Shown: a woman with deep brown skin and a rounded afro in a rose bra.

34DD

your size

36D: band 36 in, same cup volume. Shown: a woman with tan skin and long dark curls in a black bra.

36D

looser band

Same cups, three bands: 32E, 34DD, 36D hold the same cup volume.

Tape measurements that give 34DD

Computed by the Bra Atlas engine with the measured-band method, and checked by running each pair back through it.

Underbust and bust for 34DDThese are examples from our measured-band rule; other calculators can round fractional measurements differently.
Snug underbustFullest bustResult
33 in (84 cm)38.5 in (98 cm)34DD
33.5 in (85 cm)38.75 in (98 cm)34DD
34 in (86 cm)39 in (99 cm)34DD
34.5 in (88 cm)39.25 in (100 cm)34DD

Our +4 comparison gives 38A for 34 in underbust and 39 in bust. With an odd 33 in underbust and a 38 in bust we print 34D/DD; our fixture-backed model of calculator.net's unpadded row gives 34DD. How the +4 and measured-band methods work.

What is particular about 34DD

The most reported size in one UK study

White and Scurr (Ergonomics, 2012) recruited 45 women in the UK; the size they most often reported wearing was 34DD. Measured with the traditional method, the group's bands came out too big and cups too small compared with professional fitting criteria. If you have worn 34DD for years, measure again with the measured-band method before you buy.

Where the labels split

In our standard conversion, 34DD reads the same on UK and US labels. Its tighter sister is UK 32E or US 32DDD. M&S's US chart differs, printing UK 34DD as US 34D.

What the +4 method does to this body

A 34 in underbust and a 39 in bust measure 34DD. Our +4 comparison gives 38A: the band padded by 4 in, the cup from 39 − 38 = 1 in.

34DD in every system

34DD and its sisters on six labelsEach row has the same sister-size volume index. These are conversion-model labels, not proof a brand makes each size; check the brand chart before ordering.
UKUSEUFRAUJP (approx.)
30F30G65G80G8FH65
32E32DDD70F85F10EG70
34DD34DD75E90E12DDF75
36D36D80D95D14DE80
38C38C85C100C16CD85

Other sizes and tools

Sources

Each source was opened and checked on the date shown, or on 25 September 2026. Where sources disagree, the page says so instead of picking one silently.

  1. White J, Scurr J. Evaluation of professional bra fitting criteria for bra selection and fitting in the UK. Ergonomics 2012;55(6):704-711: 45 women; the traditional method overestimated band and underestimated cup
  2. Wikipedia, "Bra size": UK and US cup ladders, the +4 method, EN 13402 and JIS cup steps
  3. A Bra That Fits calculator (community calculator of r/ABraThatFits): we submitted 18 measurement pairs in 6 systems on 25 September 2026; raw synthetic fixture outputs are linked from the methodology
  4. Victoria's Secret Customer Care, "Size & Fit: International Size Chart (Outside the U.S.)": US sizes sold; bands 30 to 44, cups AA to DDD; US DDD = UK E (opened 25 September 2026)
  5. Wacoal, "International Size Guide": UK AA to GG paired with US AA to J; AUS/NZ keeps FF and GG; band and cup rows are separate, not a stock list (opened 13 October 2026)
  6. Marks & Spencer US, "Bras size guide": UK, AU/NZ, US/CA, EU and FR conversion table (opened 25 September 2026)