Bra size calculator

Work out your bra size from your underbust and bust measurements, with UK, US, EU, French, Italian and Australian sizes and sister sizes.

Take your two measurements

The result appears as soon as both measurements are entered. Use a soft tape measure, kept level, over an unpadded bra.

Just under the bust, tape snug, after breathing out.

Around the fullest part of the bust, without pulling tight.

Method & sources

The calculation follows the European EN 13402 standard: the underbust is rounded to the nearest 5 cm to give the band, and the cup follows the gap between bust and underbust, one cup every 2 cm (about 1 in) from 10 cm (AA). The size is then converted into the other systems.

Formula
EU band = underbust rounded to 5 cm · Cup = (bust − underbust − 10 cm) ÷ 2 cm: AA, A, B, C, D, DD… · UK and US band = 32 + 2 × (EU band − 70) ÷ 5

Limitations

  • UK, US, Italian and Australian equivalents follow the most common tables; some brands use their own charts.
  • The shape of the bust, the stretch and the cut of a bra cannot be read from two measurements.
  • The table covers bands 28 to 50 (EU 60 to 115) and cups AA to GG; beyond that, check the manufacturer.

Sources