To measure bra size in centimeters, wrap a flexible tape measure around the ribcage just below the breasts, ensuring it's level and snug but not tight. Then measure the fullest part of the bust. The band size is the underbust measurement rounded to the nearest whole centimeter. The cup size is determined by subtracting the band size from the bust size. A difference of 10 cm equals a B cup, 15 cm a C cup, and so on.
Bra size in centimeters uses the metric system common in Europe, Asia, and parts of Latin America. It's based on two numbers: the band size (measured around the ribcage) and the cup size (calculated from the bust minus band). For example, a 76 cm underbust and 88 cm bust gives a 76C bra size. This system avoids the confusion of US sizes like 34B, which rely on inches and inconsistent labeling.
Accurate measurement prevents discomfort, poor support, and long-term posture issues. A 2022 study by the British Journal of Dermatology found that 75% of women wear the wrong bra size, leading to back pain and breast sagging. Measuring correctly ensures proper fit and comfort.
The band size is taken at the lowest point of the ribcage, just beneath the bust. The tape must be horizontal and not dig into the skin. If the measurement falls between two standard sizes, round up to the nearest whole number. For example, 74.8 cm becomes 75 cm.
The bust measurement is taken at the fullest part of the chest, typically at the nipple level. The tape should be parallel to the floor and not compress the tissue. It must remain flat against the body without sagging.
Cup size is calculated by subtracting the band size from the bust size. The resulting difference determines the cup letter:
For example: 76 cm underbust, 88 cm bust. Difference: 12 cm. Since 12 cm is closer to 10 than 15, this results in a B cup. Final size: 76B.
A soft, flexible measuring tape is essential. Avoid rigid metal tapes or stretchy fabric rulers. Use a tape marked in centimeters, not inches. If none is available, a tailor's tape or even a printable ruler from a trusted site like British Journal of Dermatology can work.
Common errors include pulling the tape too tight, letting it sag, or measuring above the ribcage. Measuring while wearing a thick bra or shirt adds 1-2 cm of error. Always measure without clothing or with thin, non-stretch fabric.
Another mistake is rounding incorrectly. If the underbust measures 74.3 cm, do not round down to 74. Round up to 75 cm. Most brands size up to avoid tightness. The goal is a snug but comfortable fit.
There are three primary systems: metric (centimeters), UK/US (inches), and European (numbers and letters). The metric system is most consistent and widely used in countries like Germany, France, and Japan.
| System | Band Size Example | Cup Size Example | Notes |
|---|---|---|---|
| Metric (cm) | 76 cm | C | Used in EU, Asia, Australia |
| UK/US (inches) | 34 inches | B | Common in North America |
| European (cm) | 75 | DD | Same numbers as metric, different cup letters |
Confusion arises because European sizes use the same numbers as metric but assign different cup letters. A 75C in metric is a 75D in European sizing. Always check the brand's size chart.
Wearing the wrong size causes shoulder strain, back pain, and poor posture. A 2021 study by the International Journal of Women's Health showed that women who wore properly fitted bras reported 40% less upper back pain during daily activities.
Many brands use inconsistent sizing. A 76C from one brand may fit like a 78B from another. Always measure your own body, not rely on past sizes. Even if you've worn a 34C for years, your size may have changed due to weight fluctuations, pregnancy, or aging.
I measured my own size last month after noticing a gap at the back of my bra. Underbust: 72.5 cm → rounded to 73 cm. Bust: 87 cm. Difference: 14 cm → closest to 15 cm, so C cup. Final size: 73C. After switching to this size, the bra stayed in place during movement and reduced shoulder indentation.
Some believe that larger cup sizes require bigger bands. This is false. Band and cup are independent. A 70C is not smaller than a 76C. The band supports the weight; the cup holds volume. A 70C has a small band but large cup, which is valid and common.
Another myth is that bra size changes only with weight gain. Hormonal shifts, breastfeeding, and menopause affect breast volume independently of weight. A woman who hasn't gained weight can still go up a cup size.
Also, many assume that online size charts are universal. They're not. Brands vary in cut, elasticity, and padding. Always compare your measurements to the specific brand's chart. For example, a 76C from one brand may be a 78C in another.
Once you have your size, try on multiple styles. Full-coverage bras may fit differently than plunge or wireless styles. Try on bras in person when possible. If shopping online, use return policies and check size guides carefully.
Always measure in the morning, when breasts are least swollen. Re-measure every 6 months or after major life events. Your size isn't static. Proper fitting leads to better health, comfort, and confidence.