Find your estimated US bra size by accurately measuring your underbust and bust. This calculator uses a common method for determining band and cup size based on these measurements.
Measure tightly around your ribcage, directly under your bust, exhaling fully.
Measure around the fullest part of your bust, keeping the tape level.
Understanding US Bra Sizing
Finding the right bra size is crucial for comfort, support, and the overall look of your clothing. A well-fitting bra can make a significant difference in how you feel throughout the day. The US bra sizing system uses a combination of a number (for the band size) and a letter (for the cup size) to indicate the dimensions of the bra.
How to Measure for Bra Size
Accurate measurements are the foundation of finding your correct bra size. Here's how to take them:
Snug Underbust Measurement: Wrap a soft measuring tape snugly around your ribcage, directly under your bust. Make sure the tape is level all the way around your back. Exhale fully to get the smallest measurement. This measurement helps determine your band size.
Bust Measurement: Wrap the measuring tape around the fullest part of your bust (usually across the nipples). Ensure the tape is level and not too tight or too loose. This measurement, in conjunction with your band size, helps determine your cup size.
It's best to take these measurements while wearing a non-padded, unsupportive bra or no bra at all for the most accurate results.
The Calculation Explained
The calculator uses a widely accepted method for US bra sizing:
Band Size: Your snug underbust measurement is rounded to the nearest whole number. If this number is odd, 1 inch is added to make it an even number. This even number is your estimated band size (e.g., 30, 32, 34).
Cup Size: The difference between your bust measurement and your calculated band size determines your cup size. Each inch of difference corresponds to a specific cup letter:
0 inches: AA
1 inch: A
2 inches: B
3 inches: C
4 inches: D
5 inches: DD (or E)
6 inches: DDD (or F)
7 inches: G
8 inches: H
9 inches: I
10 inches: J
And so on…
Tips for Finding Your Best Fit
Bra Sister Sizes: If your calculated size doesn't feel quite right, you might try "sister sizes." For example, a 34B has the same cup volume as a 32C (down a band, up a cup) or a 36A (up a band, down a cup).
Try On Different Brands: Bra sizing can vary slightly between brands. What's a perfect fit in one brand might be slightly off in another. Always try on bras before purchasing.
Check the Fit:
Band: The band should be snug and level across your back, not riding up. You should be able to fit two fingers comfortably under the band.
Cups: Your breasts should fill the cups without spilling over the top or sides, and there should be no gaping.
Straps: Straps should provide minimal lift; most of the support comes from the band.
Center Gore: The center panel between the cups (gore) should lie flat against your sternum.
This calculator provides an excellent starting point, but personal preference and trying on bras are key to finding your perfect fit.