What You Need

  • A soft measuring tape
  • A well-fitting bra or a sports bra (wear one while measuring for best accuracy)
  • A mirror or a helper

Step 1: Measure Your Band Size

  1. 1

    Measure around your ribcage directly under your bust

    Wrap the tape measure around your body directly under your bust — where the band of a bra would sit. Keep the tape parallel to the floor and snug but not tight. Breathe out normally and read the measurement in centimetres.

  2. 2

    Round to the nearest even number

    Band sizes are even numbers (60, 65, 70, 75, 80, 85, 90 etc in Australian/European sizing, or 28, 30, 32, 34, 36 in UK/US sizing). Round your measurement to the nearest band size. In Australia and Europe, the band measurement in cm is the band size. In UK/US sizing, the measurement in inches becomes the band size (e.g. 32 inches = size 32).

Step 2: Measure Your Bust

  1. 3

    Measure around the fullest part of your chest

    Place the tape measure around the fullest part of your bust, keeping it parallel to the floor. Do not pull tight — let the tape sit on the surface. Note the measurement in centimetres (or inches for UK/US sizing).

Step 3: Calculate Your Cup Size

  1. 4

    Subtract band measurement from bust measurement

    The difference between your bust and band measurements determines your cup size. Use the chart below:

Cup Size Chart (Difference in cm for AU/EU, inches for UK/US)

  • Less than 1cm / 0 inches = AA cup
  • 1–2cm / 1 inch = A cup
  • 2–3cm / 2 inches = B cup
  • 3–4cm / 3 inches = C cup
  • 4–5cm / 4 inches = D cup
  • 5–6cm / 5 inches = DD/E cup
  • 6–7cm / 6 inches = F cup
  • 7–8cm / 7 inches = FF/G cup
ExampleBand measurement: 75cm → size 75. Bust measurement: 90cm. Difference: 90 − 75 = 15cm. That is a D cup. Full size: 75D.
Measurements are a starting pointBra sizing varies between brands. Always try bras on — the band should sit level and firm, the underwire should lie flat against your chest, and there should be no spillage over or gapping at the cups. Sizes across brands can vary by a full cup.

Frequently Asked Questions

The band should be level all the way around and you should only be able to fit two fingers under it comfortably. The underwire should lie flat against your ribcage and not dig in. Cups should contain all breast tissue without gaping or overflowing. Straps should not dig in or fall off. Start on the loosest hook and size up as the band stretches over time.
Try both sizes. If the band feels too tight in your calculated size, go up one band size and down one cup size (sister sizing). If the band is loose, go down one band size and up one cup size. For example, if 14C feels too loose in the band, try 12D — the cup volume is the same.