JJ Cup Size (UK)
A JJ cup is a UK cup letter for a bust measurement 14 inches larger than the band, the fourteenth position, one below K. It is beyond the US alphabet and an EU N.
What is a JJ cup?
A JJ cup in UK sizing means the fullest bust measurement is 14 inches (≈ 36 cm) larger than the underbust band. In US sizing the same 14-inch difference is labelled beyond K; in EU sizing N. It is not a fixed volume: what the cup holds grows with the band it sits on.
Same letter, nine volumes. A 28JJ and a 44JJ are both “JJ cups”: the second holds several times the volume of the first.
Every JJ-cup size
The same 14-inch difference on each band. Read across for measurements, sister sizes and the EU / FR / AU labels; tap a size for its full guide.
| Size | Underbust | Bust | Sister sizes | EU · FR · AU |
|---|---|---|---|---|
| 28JJ | 27–28″ · 69–71 cm | 42″ · 107 cm | — · 30J | 60N · 75N · 6JJ |
| 30JJ | 29–30″ · 74–76 cm | 44″ · 112 cm | 28K · 32J | 65N · 80N · 8JJ |
| 32JJ | 31–32″ · 79–81 cm | 46″ · 117 cm | 30K · 34J | 70N · 85N · 10JJ |
| 34JJ | 33–34″ · 84–86 cm | 48″ · 122 cm | 32K · 36J | 75N · 90N · 12JJ |
| 36JJ | 35–36″ · 89–91 cm | 50″ · 127 cm | 34K · 38J | 80N · 95N · 14JJ |
| 38JJ | 37–38″ · 94–97 cm | 52″ · 132 cm | 36K · 40J | 85N · 100N · 16JJ |
| 40JJ | 39–40″ · 99–102 cm | 54″ · 137 cm | 38K · 42J | 90N · 105N · 18JJ |
| 42JJ | 41–42″ · 104–107 cm | 56″ · 142 cm | 40K · 44J | 95N · 110N · 20JJ |
| 44JJ | 43–44″ · 109–112 cm | 58″ · 147 cm | 42K · — | 100N · 115N · 22JJ |
The JJ cup, in numbers
Volume is the pairing, not the letter. At 14 inches of difference the cup is beyond the range the clinical weight studies covered, so this site does not print a weight; on a 34 band its sisters are 32K and 36J.
Is a JJ cup big?
Fourteen inches of difference is one step from the top of the widely manufactured ladder. Weight is beyond the clinical studies this site cites; support is entirely about the band and the seaming.
Sizes this deep are where between-sizes advice reverses: sizing the band up to find a cup on the rail produces a bra that carries nothing, so the correct move is to change brand, not band.
Key takeaway: “JJ cup” describes a 14-inch difference in UK letters. Volume depends on the band; convert by position, never by letter.
What people get wrong about JJ cups
Measured JJ, sold something else?
Add-inches charts cannot produce a JJ: they inflate the band and hand the wearer a larger cup that stands off the chest. Measured snugly, the band is right and the cup comes from a specialist.
JJ cup in US, EU and other systems
4″ difference. Matches UK and EU letters.
Identical to US. Full-bust specialists (Panache, Freya, Curvy Kate) label in UK letters.
Identical to US. FR, IT, DE and JP use EU cup letters.
Convert any exact size with the size converter.
Bra styles that fit a JJ cup
Seamed full cups, side slings, wide firm bands, longlines. Expect a handful of styles per brand.
Frame like a 28 band, also look for narrower wires and shorter straps The same JJ cup is deeper and narrower here.
The widest choice of styles at this cup. Molded for a smooth line, seamed for shape and lift.
The JJ cup is wider and shallower; prioritise a firm, wide band and a wire that fully encloses the root. Longline and three-hook styles help.
Shape matters as much as size: see the fit guide for the five breast shapes and the constructions that suit each.
JJ cup: answered
How big is a JJ cup?
A JJ cup is a bust 14 inches (36 cm) larger than the band, the fourteenth UK cup letter, one below K. It is beyond the standard US alphabet and equivalent to an EU N.
What is a JJ cup in US sizes?
There is no standard US letter this deep; K is the last US position. Brands extend their alphabets individually.
Is JJ bigger than K?
No: in UK sizing K is the fifteenth position, one inch deeper than JJ.
What are the sister sizes of a 32JJ?
A 30K and a 34J in UK letters.
Which brands make JJ cups?
Panache, Elomi and Curvy Kate on select styles, generally on 30 to 40 bands. The dossiers record the exact coverage.
Opens HauteFlair’s own hub page; use your measured size there. HauteFlair is owned by the same company as Brasize.ai; that relationship never changes the sizing math, charts, or fit advice on this page. How this site makes money.
Find your exact size
A cup letter is only half the answer. Two measurements give you both halves.
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