# Bra Size Calculator

> Find your European bra size from underbust and bust measurements in cm or inches, using the EN 13402 band and cup ranges.

Category: Everyday tools · Applies to: Worldwide · Last updated: 2026-10-29
Interactive calculator: https://calculators.geekmidst.com/calculators/bra-size-calculator

European bra sizes come straight from two tape measurements: the band is your underbust rounded to the nearest 5 cm, and the cup letter steps up every 2 cm of difference between bust and underbust.

Also called: EU bra size calculator, Cup size calculator.

## Inputs
- Measurements in (options: cm, inches; default cm)
- Underbust (snug, around the ribcage) (default 87)
- Bust (around the fullest part) (default 107)

## Results
- European size (EN 13402)
- Band
- Cup
- Bust minus underbust

## Formula

```
Band = underbust rounded to the nearest 5 cm;  Cup from (bust − underbust): over 10–12 cm AA, 12–14 A, 14–16 B, 16–18 C, 18–20 D, 20–22 E, 22–24 F, 24–26 G, 26–28 H
```

Where:
- Underbust: measured snugly just below the bust
- Bust: measured loosely around the fullest part

## Worked example
1. Band: 87 cm rounds to the nearest 5 cm, 85.
2. Difference: 107 − 87 = 20 cm.
3. 20 cm falls in the over-18-to-20 cm range, cup D.

**Result:** An underbust of 87 cm and a bust of 107 cm give a European size of 85D.

## What the result means

Treat the result as a starting size to try on. Fit varies by brand and style, and UK and US sizes use inch bands and different letters above D, so the same measurements can carry a different label there.

## Assumptions and limits
- EN 13402 European size ranges, as tabulated by mobilefish.com.
- Measurements taken while wearing a non-padded bra or none, tape level all round.
- UK and US sizes are not converted: their cup sequences differ between countries and brands.
- The table covers cups AA to H and bands 60 to 125.

## Questions

### Why does my size differ between shops?

Brands cut differently and UK, US, French and Australian sizes use other band numbers and cup letters. Use your measurements and each brand’s chart.

### What if I am between two cups?

The cup changes every 2 cm; if you are right on a boundary, try both sizes.

## Sources
- [EN 13402 cup and band size table (mobilefish.com)](https://www.mobilefish.com/popupwindow/en13402_pictogram_help_all.php?help=cup)

## Related calculators
- [Length Converter](https://calculators.geekmidst.com/calculators/length-converter)
- [Height Calculator](https://calculators.geekmidst.com/calculators/height-calculator)

Source: GM¹X CalcVerse — https://calculators.geekmidst.com/calculators/bra-size-calculator