Size guide
How to measure, the band and cup chart, sister sizes and the fit checklist — without the +4 myth.
How to measure
You need a soft measuring tape and a mirror. Wear an unpadded bra if you have one; if not, measure against the body. Keep the tape snug but not tight.
- Underbust: wrap the tape around your ribcage, directly under the bust, and breathe out.
- Full bust: wrap the tape around the fullest part of the bust, keeping it parallel to the floor.
- Cup difference: full bust minus underbust, in centimetres.
Do not add four inches. The old +4 method is why so many women wear a band that rides up. Use the actual underbust measurement.
Band & cup chart
| Underbust (cm) | Band |
|---|---|
| 63–67 | 30 |
| 68–72 | 32 |
| 73–77 | 34 |
| 78–82 | 36 |
| 83–87 | 38 |
| 88–92 | 40 |
| 93–97 | 42 |
| 98–102 | 44 |
| 103–107 | 46 |
| Bust − underbust (cm) | Cup |
|---|---|
| Up to 2.5 | AA |
| 2.5–5 | A |
| 5–7.5 | B |
| 7.5–10 | C |
| 10–12.5 | D |
| 12.5–15 | DD / E |
| 15–17.5 | F |
| 17.5–20 | G |
| 20–22.5 | H |
Example: underbust 78 cm → band 36; full bust 96 cm → difference 18 cm → G cup. Start at 36G, then try the sister sizes.
Sister sizes
Sister sizes hold the same cup volume on a different band. If 36D is tight in the band but right in the cup, try 38C.
| Your size | Sister down | Sister up |
|---|---|---|
| 34C | 32D | 36B |
| 36DD | 34E | 38D |
| 38F | 36G | 40E |
| 40H | 38I / J | 42G |
The fit checklist
- Band: level all the way round, snug enough not to ride up when you lift your arms.
- Cup: no spilling, no gaping, no digging wire. Centre panel flat against the sternum.
- Straps: should not carry the whole bra or leave deep marks.
- Underwire: sits flat against the ribcage, not on breast tissue.
- Movement: bend forward, reach up, sit down. The bra should stay in place.
International conversions
| Kenya / UK | US | EU | FR |
|---|---|---|---|
| 32B | 32B | 70B | 85B |
| 34C | 34C | 75C | 90C |
| 36D | 36D | 80D | 95D |
| 38DD | 38DD/E | 85DD | 100DD |
| 40F | 40F | 90F | 105F |
Get a second opinion
Send your underbust and full-bust measurements, the style you are looking at and what your current bra does wrong. A fit specialist will reply with a size and a sister size. Message us or take the quiz.