Bra AtlasBra sizing, measured and sourced

38D sister size chart, conversions and measurements

38D has sisters 36DD and 40C, and the UK and US labels agree at this size and both of them. Our +4 comparison would put the same body in 42AA, two volume steps smaller.

Bra Atlas fitting card

38DUK · same in the US

Measures about 38 in underbust and 42 in bust. Same cups as 36DD and 40C.

UK
38D
US
38D
EU
85D
FR
100D
AU
16D
JP
E85

Same cups 36DD38D40C

Every sister of 38D

  • 34ETighter band by 4 in, 2 cup letters up (US 34DDD, EU 75F)
  • 36DDTighter band by 2 in, 1 cup letter up (US 36DD, EU 80E)
  • 38DThis size (US 38D, EU 85D)
  • 40CLooser band by 2 in, 1 cup letter down (US 40C, EU 90C)
  • 42BLooser band by 4 in, 2 cup letters down (US 42B, EU 95B)

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

36DD: band 36 in, same cup volume. Shown: a woman with light skin and straight black hair with a fringe in a sage bra.

36DD

tighter band

38D: band 38 in, same cup volume. Shown: a woman with deep brown skin and a rounded afro in a rose bra.

38D

your size

40C: band 40 in, same cup volume. Shown: a woman with tan skin and long dark curls in a black bra.

40C

looser band

Same cups, three bands: 36DD, 38D, 40C hold the same cup volume.

Tape measurements that give 38D

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

Underbust and bust for 38DThese are examples from our measured-band rule; other calculators can round fractional measurements differently.
Snug underbustFullest bustResult
37 in (94 cm)41.5 in (105 cm)38D
37.5 in (95 cm)41.75 in (106 cm)38D
38 in (97 cm)42 in (107 cm)38D
38.5 in (98 cm)42.25 in (107 cm)38D

Our +4 comparison gives 42AA for 38 in underbust and 42 in bust. With an odd 37 in underbust and a 41 in bust we print 38C/D; our fixture-backed model of calculator.net's unpadded row gives 38D. How the +4 and measured-band methods work.

What is particular about 38D

What the +4 method does to this body

A 38 in underbust and a 42 in bust measure 38D. Our +4 comparison pads the band to 42, exactly the bust measurement, and returns 42AA: four cup letters down and two band sizes up from 38D, and two sister-size volume steps smaller, the direction White and Scurr (2012) measured in UK fittings.

Which sister to try

If a 38D band rides up, 36DD is the tighter sister. If it digs in, 40C. 34E (US 34DDD) and 42B are two steps away on either side.

Reading it elsewhere

38D converts to EU 85D, France 100D, Australia 16D and roughly E85 in Japan. The UK and US labels agree at this size and its immediate sisters.

38D in every system

38D 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.)
34E34DDD75F90F12EG75
36DD36DD80E95E14DDF80
38D38D85D100D16DE85
40C40C90C105C18CD90
42B42B95B110B20BC95

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. 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)
  4. 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)
  5. Marks & Spencer US, "Bras size guide": UK, AU/NZ, US/CA, EU and FR conversion table (opened 25 September 2026)