UK to US Bra Size
Use the band row first, then check how the specific US brand names the same cup volume.
Illustrative band-label comparison — not the US/UK fitting calculator
The centimeter underbust intervals below follow a Wacoal Singapore/Japanese-style reference, paired with illustrative US/UK and EU band labels. They are not the US Knix or UK Brastop underbust formulas used by our calculator. Do not use this cross-reference to derive a cup size or assume identical fit across brands. Source: Wacoal Singapore guide.
| Underbust | US | UK | EU |
|---|---|---|---|
| 68–72 cm | 32 | 32 | 70 |
| 73–77 cm | 34 | 34 | 75 |
| 78–82 cm | 36 | 36 | 80 |
| 83–87 cm | 38 | 38 | 85 |
| 88–92 cm | 40 | 40 | 90 |
| 93–97 cm | 42 | 42 | 95 |
Band-label methods differ across makers. These are printed band references, not the actual underbust-to-band mapping of Knix or Brastop. For a starting physical measurement use the source-specific calculator.
Illustrative cup-letter sequence (not a fitting formula)
| Example inch step (not paired with band table) | US | UK |
|---|---|---|
| 1 in / 2.5 cm | A | A |
| 2 in / 5 cm | B | B |
| 3 in / 7.5 cm | C | C |
| 4 in / 10 cm | D | D |
| 5 in / 12.5 cm | DD/E | DD |
| 6 in / 15 cm | DDD/F | E |
The cup rows are illustrative US/UK naming examples, not a verified measurement-to-size chart for either Knix or Brastop. Larger cup letters, labels like DD/E and complete US ↔ UK bra sizes are brand/system dependent. Never combine these rows with the centimeter band comparison to compute a fitted size.
Convert the UK band first, then verify the US cup sequence
Treat the band numbers as approximate printed-label cross-references, not the Knix US or Brastop UK fitting method. Check the source-specific chart before using the US reference.
Do not carry the cup letter across unchanged. UK and US cup naming can diverge, especially beyond the early letters, so compare the full size with the brand chart.
Use sister sizing only after the system conversion
If the converted band feels wrong but cup volume seems close, evaluate a sister size within the destination system rather than mixing two conversion steps at once.
Shape, wire width and cup depth can still make a mathematically plausible converted size fit poorly.
How this guidance is checked
These sources support the measurement method and help check real-world variation. They are not presented as one universal brand-size table.
- Bra Fit Calculator — Wacoal. Bra measurement cross-check using underbust and fullest-bust measurements and brand-specific fitting logic.
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