FF Cup Size (UK)
An FF cup is a UK cup letter for a bust measurement 8 inches larger than the band. It sits between F and G on the UK ladder, and it is a US H and an EU H.
What is an FF cup?
A FF cup in UK sizing means the fullest bust measurement is 8 inches (≈ 20 cm) larger than the underbust band. In US sizing the same 8-inch difference is labelled H; in EU sizing H. It is not a fixed volume: what the cup holds grows with the band it sits on.
Same letter, nine volumes. A 28FF and a 44FF are both “FF cups”: the second holds several times the volume of the first.
Every FF-cup size
The same 8-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 |
|---|---|---|---|---|
| 28FF | 27–28″ · 69–71 cm | 36″ · 91 cm | — · 30F | 60H · 75H · 6FF |
| 30FF | 29–30″ · 74–76 cm | 38″ · 97 cm | 28G · 32F | 65H · 80H · 8FF |
| 32FF | 31–32″ · 79–81 cm | 40″ · 102 cm | 30G · 34F | 70H · 85H · 10FF |
| 34FF | 33–34″ · 84–86 cm | 42″ · 107 cm | 32G · 36F | 75H · 90H · 12FF |
| 36FF | 35–36″ · 89–91 cm | 44″ · 112 cm | 34G · 38F | 80H · 95H · 14FF |
| 38FF | 37–38″ · 94–97 cm | 46″ · 117 cm | 36G · 40F | 85H · 100H · 16FF |
| 40FF | 39–40″ · 99–102 cm | 48″ · 122 cm | 38G · 42F | 90H · 105H · 18FF |
| 42FF | 41–42″ · 104–107 cm | 50″ · 127 cm | 40G · 44F | 95H · 110H · 20FF |
| 44FF | 43–44″ · 109–112 cm | 52″ · 132 cm | 42G · — | 100H · 115H · 22FF |
The FF cup, in numbers
Volume is the pairing, not the letter. On a 34 band a FF cup holds about 920 g per breast by the clinical estimates; on a 40 band about 1965 g. Its sisters on a 34 are 32G and 36F.
Is an FF cup big?
Eight inches of difference is firmly full-bust: above the 500-gram-per-breast line on every band from 30 up, and the point where mainstream US ranges have long since stopped. It is also one of the most common sizes at UK full-bust specialists, which cut FF as a matter of course.
The FF sits exactly where US and UK notation are furthest apart in daily use: a UK FF is a US H, and a US customer who reads FF as "F and a bit" buys two cups small.
Key takeaway: “FF cup” describes a 8-inch difference in UK letters. Volume depends on the band; convert by position, never by letter.
What people get wrong about FF cups
Wearing an FF cup on a band that rides up?
The old +4 rule inflates the band by four inches and understates the cup by two letters. If a chart gave you a FF cup on a loose band, the snug-measure equivalent is two bands down and two cups up: the same volume, carried by the band.
| If a +4 chart said | Snug-measure size is likely | Same volume? |
|---|---|---|
| 32FF | 28GG | Yes: the band supports instead of the straps |
| 34FF | 30GG | Yes: the band supports instead of the straps |
| 36FF | 32GG | Yes: the band supports instead of the straps |
| 38FF | 34GG | Yes: the band supports instead of the straps |
| 40FF | 36GG | Yes: the band supports instead of the straps |
FF 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 an FF cup
Deep cups reward structure: seamed full cups, side-support balconettes and stretch-lace tops follow the tissue; moulded cups at this depth are rare and often collapse.
Frame like a 28 band, also look for narrower wires and shorter straps The same FF 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 FF 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.
FF cup: answered
How big is an FF cup?
An FF cup is a bust 8 inches (20 cm) larger than the band, the eighth UK cup letter. On a 34 band that is about 920 g per breast by the clinical estimates; on a 40 band roughly 1.9 kg. Its US equivalent is H and its EU equivalent is H.
What is an FF cup in US sizes?
A US H. UK letters after DD run E, F, FF, G, GG, H; US letters run DDD, G, H, I. Position eight is FF in the UK and H in the US. Never match the letters: a US F does not exist and a US G is one cup smaller than a UK FF.
Is FF bigger than G?
In UK sizing, no: FF is the eighth cup and G the ninth, so a UK G is one inch deeper. Against a US G, yes: a US G is the seventh position, one cup smaller than a UK FF.
What are the sister sizes of a 34FF?
A 32G and a 36F in UK letters hold the same volume as a 34FF. Go down a band and up a letter, or up a band and down a letter.
Which brands make FF cups?
UK full-bust specialists carry FF as a core size: Panache, Freya, Fantasie, Curvy Kate and Elomi all cut it across most of their band ranges. US brands that reach the same volume label it H.
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.
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