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 36DD·38D·40C
38D sister sizes, conversions and measurements
38D is a common band-and-cup pairing (1,300 US searches a month for its sister size, 1,900 for "38d bra size" outright), and one of the few sizes here where the +4 method still returns a size, just the wrong one.
Every sister of 38D
- 32FTighter band by 6 in, 3 cup letters up (US 32G, EU 70G)
- 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)
- 44ALooser band by 6 in, 3 cup letters down (US 44A, EU 100A)
36DD
tighter band
38D
your size
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.
| Snug underbust | Fullest bust | Result |
|---|---|---|
| 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 |
Same body, other methods: 38 in and 42 in is a 42AA with the traditional +4 method. With an odd 37 in underbust and a 41.5 in bust we print 38D; calculator.net's rule (band rounded, cup from the raw difference) would print 38DD. Why methods differ.
What is particular about 38D
"38d sister size" gets about 1,300 Google searches a month in the US and 140 in the UK (Google Ads data, September 2026).
What the +4 method does to this body
A 38 in underbust and a 42 in bust measure 38D. The +4 method pads the band to 42, exactly the bust measurement, and returns 42AA: four cup letters down and two band sizes up from 38D, and a much smaller cup volume, 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 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
| UK | US | EU | FR | AU | JP (approx.) |
|---|---|---|---|---|---|
| 32F | 32G | 70G | 85G | 10F | H70 |
| 34E | 34DDD | 75F | 90F | 12E | G75 |
| 36DD | 36DD | 80E | 95E | 14DD | F80 |
| 38D | 38D | 85D | 100D | 16D | E85 |
| 40C | 40C | 90C | 105C | 18C | D90 |
| 42B | 42B | 95B | 110B | 20B | C95 |
| 44A | 44A | 100A | 115A | 22A | B100 |
Other sizes and tools
- Bra size calculatorCheck that 38D is still your size, with both methods shown
- Sister size chartThe full diagonal chart and fit fixes
- Fit checkTick what feels wrong in your 38D; get the size to try next
- Brand size chartsHow Victoria's Secret, ThirdLove, Wacoal, SKIMS, M&S and Freya label 38D
- D cup, explainedWhat the D cup means, and why it changes by band
- 30DSister sizes, conversions and measurements
- 32DDSister sizes, conversions and measurements
- 34BSister sizes, conversions and measurements
- 34CSister sizes, conversions and measurements
- 34DSister sizes, conversions and measurements
- 34DDSister sizes, conversions and measurements
- 36CSister sizes, conversions and measurements
- 36DDSister sizes, conversions and measurements
Sources
Each source was opened and checked on 25 September 2026. Where sources disagree, the page says so instead of picking one silently.
- 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
- Wikipedia, "Bra size": UK and US cup ladders, the +4 method, EN 13402 and JIS cup steps