Find your perfect bra size by measuring your band and bust.
Understanding Your Bra Size
Determining the correct bra size is essential for comfort, support, and a flattering silhouette. The US bra sizing system primarily relies on two measurements: the band size and the cup size.
How the Calculator Works:
This calculator uses standard methods for determining bra size in the US market. It takes two key measurements from you:
Band Measurement (Underbust): This is the measurement around your ribcage directly under your breasts. It's crucial for the bra band to fit snugly but comfortably, parallel to the floor. The calculator expects this in inches.
Bust Measurement (Fullest Part): This is the measurement around the fullest part of your bust, usually over the nipples. This measurement is used to determine your cup size. The calculator expects this in inches.
The Calculation Logic:
1. Band Size Determination:
The calculator first rounds your Band Measurement (underbust) to the nearest even number. For example, a measurement of 31.5 inches would typically be rounded to 32 inches for the band size. Some systems may add a small amount (e.g., 4-5 inches) to the underbust measurement before rounding, depending on the brand's specific sizing chart. For simplicity, this calculator uses the rounded underbust measurement directly as the band size.
2. Cup Size Determination:
The cup size is determined by the difference between your Bust Measurement and your Band Measurement.
A difference of 1 inch = A cup
A difference of 2 inches = B cup
A difference of 3 inches = C cup
A difference of 4 inches = D cup
A difference of 5 inches = DD cup (or E cup in some systems)
A difference of 6 inches = DDD cup (or F cup)
And so on, typically adding a letter for each additional inch.
The calculator calculates this difference: Difference = Bust Measurement - Band Measurement. It then maps this difference to the corresponding US cup size letter.
Important Considerations:
Bra sizing can vary significantly between brands and even between different styles within the same brand. This calculator provides a strong starting point, but it's always recommended to try bras on whenever possible. Factors like breast shape, tissue density, and bra construction can influence the fit. If you are between sizes, it's often best to try both.
Example Calculation:
Let's say:
Your Band Measurement (underbust) is 33 inches.
Your Bust Measurement (fullest part) is 38 inches.