Cup Size Calculator

Cup Size Calculator – Find the Right Bra Size

According to studies, the majority of women wear the wrong bra size – estimates vary, but in several surveys, the figure has risen to as high as 70-80 percent. The wrong size is not only uncomfortable, but it can over time cause neck, shoulder, and back pain as well as poor posture. This calculator helps find a starting point for determining the correct size.

How to Measure Yourself Correctly

You will need a measuring tape and a mirror. Underbust measurement is taken snugly, but not too tightly, directly under the breasts – the measuring tape should run horizontally around the back. Bust measurement is taken loosely at the fullest part of the breasts, standing upright and breathing relaxed, without a bra or with light, unpadded bras.

How Do Measurement Results Convert to Size?

The band size (for example, 75 or 80) is derived from the underbust measurement, which is rounded to the nearest five centimeters in the European sizing system. The cup size, on the other hand, is determined by the difference between the underbust measurement and the bust measurement – the larger the difference, the larger the cup size. A difference of about 12-13 centimeters typically corresponds to an A cup, 14-15 centimeters to a B cup, 16-17 centimeters to a C cup, and so on, with the letter increasing approximately every two centimeters.

Sister Sizes – An Option When the Size Doesn’t Feel Right

One lesser-known but very useful concept is sister sizes. The cup volume of bras depends on both the band size and the cup letter together, so several different size combinations can effectively contain the same cup volume. When you decrease the band size by one size (for example, from 80 to 75), increase the cup size by one letter to stay in the same cup volume – and vice versa. For example, 75C, 80B, and 70D can all be sister sizes to each other.

This is especially useful if a specific brand or model doesn’t seem to fit quite right – try a sister size first before giving up on the style altogether.

Differences Between Brands Can Be Surprisingly Large

Bra sizing standards are not completely uniform among manufacturers. The same labeled size can fit very differently across different brands, styles, and even within different collections of the same brand. For this reason, the result provided by the calculator should be considered a good starting point, but whenever possible, try on the bras before making a purchase decision.

When Should You Measure Again?

• When your weight changes significantly in either direction.
• During and after pregnancy and breastfeeding, when the size can vary several times.
• If old bras start to feel uncomfortable, straps slip, or cups no longer fit perfectly.
• About once a year as a general check, since the body changes over time.

The calculator provides an estimate based on the most commonly used European measurement method. The final fit should always be confirmed by trying on.