Bra Size Chart: Measurements, Cup Sizes & Sister Sizes
Find your true bra size in about sixty seconds. Type two measurements and the chart lights up your size; or tap any cell to see the measurements that produce it, its sister sizes and how many bras we carry in it. US, UK and EU lettering, bands 28 to 48.
Each cell shows the size and the bust measurement that produces it on that band. Sizes we do not currently stock are outlined rather than filled; the chart is still correct for them. The band is your underbust rounded to the nearest even inch, no plus-four.
How to measure your bra size
Two numbers with a soft tape, one subtraction, and the chart above does the rest. Measure in a thin unlined bra or none at all, stand upright, and keep the tape level all the way round. Most people are wearing a band too loose and a cup too small, so measure fresh rather than trusting the label in your drawer.
Measure directly under your bust
Wrap the tape around your ribcage immediately beneath the breast tissue, where an underwire sits. Pull it snug, firm enough that only a finger slides underneath, because a bra band is elastic and always sits tighter than a tape. Exhale fully, then read the number and round to the nearest even inch. That is your band. A 33″ underbust is a 34; a 31″ is a 32.
Measure across the fullest part
Keep the tape level front to back and let it rest on the fullest point, usually the nipple line. Do not pull it tight; compressing the tissue shrinks your cup and is why so many people land in a D when they measure an F. Subtract your band from this number. Every whole inch of difference is one cup letter: 1 is A, 2 is B, 3 is C, 4 is D, 5 is DD.
Soft tape, or none
Fabric or vinyl; a metal tape reads long. No tape at all? Wrap a ribbon or phone cable, mark it, and lay it against a ruler.
Unpadded or bare
Padding, moulded foam and push-up all add inches that are not yours and inflate the cup.
Use a mirror
The tape has to be level across your back as well as the front. You cannot check that by feel.
Re-measure yearly
And after weight change of ten pounds, pregnancy, nursing, menopause or a new exercise routine.
Bra cup sizes explained
What A, B, C and D actually mean, and the most misunderstood thing on any chart: a cup letter is not a volume. It is the difference between your bust and your band, one letter per inch, starting at AA for no difference at all. That is why a 32D and a 36D are not the same cup, why a 32D and a 34C are, and why the letter on your old bra is a poor guide to a new brand.
| Difference | US | UK | EU | What it means |
|---|
The row for the size selected in the chart is marked. US and UK agree through DD and split at six inches, which is why the same body wears a 34DDD from an American brand and a 34E from a British one. The conversion page has all seven systems.
Same letter, different volume
A D cup on a 30 band holds roughly what a B cup holds on a 34. Every step up the band adds volume to the same letter, so the letter only means something when it is attached to its band number. Two people who both say "I'm a D" can be three cup volumes apart.
Why most people are a bigger cup than they think
The plus-four band rule pushed people into bands too big, and a bigger band means a smaller letter for the same bust. Drop from a 36 to a true 34 and a C becomes a D with nothing about you changing. Trust the measurement, not the letter you have worn for a decade.
Sister sizes, and when to use one
Sister sizes are different labels holding the same cup volume. Go down one band and up one cup, or up one band and down one cup, and the cup itself stays the same. This is the answer to a band that is wrong when the cup is right, and to a size that is sold out.
Volume is constant across the row. What changes is how firmly the band holds your ribcage, and therefore how much of the support comes from the band rather than the straps. Select a different size in the chart and the family updates.
The band rides up at the back
The band is too loose. Go down one band and up one cup. A 36C becomes a 34D. The cup is unchanged, the band finally does its job, and the straps stop digging.
The band digs in or you cannot breathe
The band is too tight. Go up one band and down one cup. A 34D becomes a 36C. Try this before assuming you need a wider back or a longer hook row.
Sister size chart, every band
| Sister down (tighter band) | Your size | Sister up (looser band) | In stock |
|---|
US, UK and EU sizes side by side
We carry US, UK and European brands together, so the number on the label depends on where the bra was cut. Bands are identical in US and UK, metric in Europe; cups agree through D and part company after it. The size selected in the chart is marked in both tables.
Band sizes, with centimetres
| US / UK | Underbust | In centimetres | EU / JP | FR / ES | AU / NZ |
|---|
The centimetre column is the underbust range the band fits, not the label. A 34B is a 34 inch band, roughly 84 to 89 cm, sold as a 75B in Europe; a 36 band is about 89 to 94 cm, an EU 80. An "80 cm bra size" on a continental label is an 80 cm underbust, the same body as a US 36.
Common sizes, converted
| US | UK | EU | FR / ES | AU / NZ | Shop |
|---|---|---|---|---|---|
| 32C | 32C | 70C | 85C | 10C | 32C |
| 32D | 32D | 70D | 85D | 10D | 32D |
| 34C | 34C | 75C | 90C | 12C | 34C |
| 34D | 34D | 75D | 90D | 12D | 34D |
| 34DD | 34DD | 75E | 90E | 12DD | 34DD |
| 34DDD | 34E | 75F | 90F | 12E | 34E |
| 36C | 36C | 80C | 95C | 14C | 36C |
| 36D | 36D | 80D | 95D | 14D | 36D |
| 36DD | 36DD | 80E | 95E | 14DD | 36DD |
| 38D | 38D | 85D | 100D | 16D | 38D |
Panache, Freya, Elomi and Fantasie print UK. Wacoal, Le Mystère and Natori print US. Chantelle prints French. For Italian, Japanese and Australian sizing, centimetre bands and a converter that takes any of the seven, use the full conversion page.
Bra sizes in order, smallest to largest
A bra size is two lists read together: bands in even inches, cups one letter per inch of difference. This is every step of both, in order, in the three lettering systems you will meet.
Bands, in order
26 · 28 · 30 · 32 · 34 · 36 · 38 · 40 · 42 · 44 · 46 · 48 · 50 · 52 · 54 · 56. The bold run is what we stock. A 26 band exists in a handful of UK brands; 50 and above come from specialist plus-size makers. Every band is an even number because the industry grades in two inch steps, which is why an odd underbust rounds to the nearest even.
Cups, in order
| System | Cups, smallest to largest |
|---|
Each column is the same cup across the three rows: a US DDD is a UK E is an EU F. AAA sits below AA in a few US brands and means a bust that measures smaller than the band; it is rare and usually better served by a bralette. Above K, UK brands go KK, L, LL and a few reach N, but only in bands 28 to 40.
The smallest bra size
In everyday retail, a 28AA or 30AA: a 28 inch band with no difference between bust and band. Some UK brands cut a 26 band and some US brands an AAA cup, but both are hard to find. If you measure below a 28, a 28 with the band on the tightest hook, a bralette or a small-cup bra with stretch will fit better than hunting for a 26.
The biggest bra size
Cups run to about K in US lettering and KK to N in UK lettering from full-bust specialists, and bands to 56 or beyond from plus-size makers, though never both at once: the deepest cups are cut in the smaller bands. The largest we carry is a 34K and 36K; the widest is a 48F. The size directory shows the real coverage.
Small, medium and large, in bra sizes
Bralettes, sports bras and sleep bras are often sized S to XL instead of by band and cup. There is no standard, and every brand's chart wins over this one, but the usual mapping is close enough to pick a starting size. "Medium" on a bra tag most often means a 34B to 36B.
| Letter size | Usually covers | Underbust |
|---|---|---|
| XS | 30A, 30B, 32A | 29–32″ |
| S | 32B, 32C, 34A | 31–34″ |
| M | 34B, 34C, 36A, 36B | 33–36″ |
| L | 36C, 36D, 38B, 38C | 35–38″ |
| XL | 38D, 40C, 40D | 37–40″ |
| 2XL | 40DD, 42C, 42D | 39–42″ |
| 3XL | 42DD, 44C, 44D | 41–44″ |
Letter sizes assume an average cup for the band. If your cup is a D or above, size up one letter or, better, choose a style cut by band and cup: our sports bras and bralettes include both kinds.
Six signs your charted size needs a nudge
The chart gives you a starting size. The bra you try on gives you the correction. Match the symptom, apply the adjustment, then come back and tap the new size to see its sisters and stock.
Browse bras by cup size
Every cup we stock, with live counts across all bands, labelled the way the bras inside are labelled. Above DD that is UK lettering, because the brands that cut those sizes are British.
Bra size chart questions, answered
How do I read a bra size chart?
How do I measure my bra size at home?
What do the cup sizes on a bra chart mean?
What is a sister size?
Should I trust the size on the bra I wear now?
Is the plus-four method accurate?
My underbust is an odd number. Which band do I pick?
How often should I re-measure?
Is a 34DDD the same as a 34E?
Do all brands follow the same chart?
What is the smallest bra size, and the biggest?
What are AA and AAA cup sizes?
What is a 34B in centimetres?
Is a 34B small? What is the average bra size?
What does "medium" mean in bra sizes?
Does the chart work for sports, strapless and nursing bras?
How this chart is built
No proprietary table. Every cell is one subtraction and one lookup, so you can check it against a bra you already own and trust.
What we deliberately do not do
No plus-four. Every row uses the direct underbust measurement.
No single house chart. The chart shows US, UK and EU lettering because the label you buy only prints one, and forcing them into one column would be wrong for two thirds of the catalogue.
No invented cells. Where we do not stock a size the cell is outlined, not hidden. The chart stays correct for it; there is simply nothing to link to yet.
No stored measurements. The two numbers you type stay in your browser.
Ranges we cover
Bands 28 to 48, cups A to K in UK lettering. Stock counts are shown per size and were last checked against the catalogue in August 2026; the size directory is the live view.
Shop it, in stock, today
555 bras from 28D through 48F, and free US shipping over $50.
Chart reviewed against UK and US brand specifications. Measurements never leave your browser.