Bra size calculator from measurements
Enter two tape measurements to get your UK, US and EU size.
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How to use it
- Enter unit, underbust, bust at fullest point and band method.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
Plus-zero: band = underbust in inches rounded to the nearest even number. Plus-four: round the underbust to the nearest inch, then add 4 if even or 5 if odd. Cup = bust minus band, rounded to the nearest inch: 0 = AA, 1 = A, 2 = B, 3 = C, 4 = D, 5 = DD, 6 = E. 1 in = 2.54 cm.
Example
Inputs: Unit = inches, Underbust = 31, Bust at fullest point = 36, Band method = Plus-zero (modern). Result: UK size: 32D; US size: 32D; EU size: 70D.
Limits and caveats
- The two methods give different bands; plus-zero is closer to what specialist fitters use.
- Shape and cut matter, so treat the result as a starting point to try on.
Questions about this tool
How do I measure the underbust?
Wrap the tape level just under the bust, snug but not pressing, while breathing out.
What is the difference between plus-zero and plus-four?
Plus-four is an older method that adds 4 or 5 inches, giving a bigger band and smaller cup. Plus-zero uses the measurement as it is.
Is each inch of difference one cup?
Yes. In UK and US sizing, each inch between bust and band moves the cup up one letter.