European bra sizes are written in centimetres: a band number such as 80 and a cup letter such as C, as in 80C. The system is defined by the standard EN 13402 and used across much of Europe and many other countries. This calculator takes your bust and underbust, applies the standard’s rules and gives your European size, the French equivalent, and a second check using the band size instead of your exact underbust.
How to use the European bra size calculator
- Measure the underbust. Wrap a tape directly under the bust, level and snug, standing up.
- Measure the bust. Wrap the tape around the fullest part of the bust, level and not tight.
- Enter both numbers in centimetres or inches.
- Read your size and compare the main result with the alternative check. If the two cup letters differ, try both.
EN 13402 bra size formulas
cup difference = bust − underbust
French band = European band + 15
The cup letter comes from the difference, in 2 cm steps. The lower value of each step is excluded and the upper value is included, which is the convention MobileFish gives for the standard (a 20 cm difference is a D, not an E). The tables below are the standard’s ranges (retrieved 2026-10-15).
| EU cup | Bust − underbust (cm) | Bust − underbust (in) |
|---|---|---|
| AA | over 10 up to 12 | over 3.94 up to 4.72 |
| A | over 12 up to 14 | over 4.72 up to 5.51 |
| B | over 14 up to 16 | over 5.51 up to 6.30 |
| C | over 16 up to 18 | over 6.30 up to 7.09 |
| D | over 18 up to 20 | over 7.09 up to 7.87 |
| E | over 20 up to 22 | over 7.87 up to 8.66 |
| F | over 22 up to 24 | over 8.66 up to 9.45 |
| G | over 24 up to 26 | over 9.45 up to 10.24 |
| H | over 26 up to 28 | over 10.24 up to 11.02 |
| EU band | Underbust range (cm) | Underbust range (in) | French band |
|---|---|---|---|
| 60 | 57.5 – 62.5 | 22.6 – 24.6 | 75 |
| 65 | 62.5 – 67.5 | 24.6 – 26.6 | 80 |
| 70 | 67.5 – 72.5 | 26.6 – 28.5 | 85 |
| 75 | 72.5 – 77.5 | 28.5 – 30.5 | 90 |
| 80 | 77.5 – 82.5 | 30.5 – 32.5 | 95 |
| 85 | 82.5 – 87.5 | 32.5 – 34.4 | 100 |
| 90 | 87.5 – 92.5 | 34.4 – 36.4 | 105 |
| 95 | 92.5 – 97.5 | 36.4 – 38.4 | 110 |
| 100 | 97.5 – 102.5 | 38.4 – 40.4 | 115 |
Worked example
The MobileFish EN 13402 help page gives this case: underbust 87 cm, bust 107 cm.
- Band: 87 ÷ 5 = 17.4, rounded to 17, times 5 = 85.
- Difference: 107 − 87 = 20 cm, which is the top of the 18 to 20 cm step, so the cup is D.
- European size: 85D; French size 100D.
- Alternative check, bust minus band: 107 − 85 = 22 cm, which gives 85E.
Reading the two results
- They agree: your underbust is close to a multiple of 5 and the size is reliable.
- They differ by a cup: your underbust is a couple of centimetres away from the nearest band. Try the main size and the alternative on the same band.
- Soft tissue: Wikipedia notes that tissue softness changes how tight the tape can be pulled, so a loose measurement of 84 cm and a snug one of 79 cm can both be correct for the same body.
The Cup Size Calculator and Band Size Calculator show each half separately, and the Bra Size Converter (US/UK/EU/AU/FR/JP) translates a result to UK, US, Australian and Japanese sizing. A fitting in a shop remains the best check, and this page is general information, not a medical or professional fitting.
Sources
Every figure above comes from these pages, read directly on the dates shown.
- MobileFish — EN 13402 pictogram help: cup and band (ranges and worked examples) — checked 2026-10-15
- Wikipedia — Brassiere measurement (European sizes, band and cup methods) — checked 2026-10-15
Frequently asked questions
What is a European bra size?
It is the size defined by the standard EN 13402-3: the band is your underbust rounded to the nearest 5 cm, and the cup letter is set by the difference between your bust and underbust in 2 cm steps. An 80C therefore has an 80 cm band and a bust 16 to 18 cm larger than the underbust.
Why is there a second size, “bust − band”?
Wikipedia explains that some methods subtract the band size, not the exact underbust, from the bust. If the two methods disagree, your underbust sits some way from the nearest multiple of 5 and it is worth trying both cup letters.
How is the French size related?
French and Spanish band numbers run 15 above the European number, so 80C in Europe is 95C in France. The cup letters are the same.
Does it work for sizes beyond H?
No. The standard table on which this page is based stops at H (26 to 28 cm). Larger and smaller differences are reported as outside the chart. See the Cup Size Calculator for a simpler version.
How accurate is a measured size?
It is a starting point. Brands cut differently, and snug versus loose measuring can move your underbust by a few centimetres, so always try the neighbouring band. Use the Bra Size Converter (US/UK/EU/AU/FR/JP) to translate it to other countries.