Find Your

Size Calculator

Knowing your proper bra size is the first step in finding the most comfortable bra for you.
Use our calculator to get your size and let us do the work for you.

Step 1
Let's Measure Your Underband

Wrap the measuring tape around your ribcage, directly under your bust, as tightly as you'd like your bra to fit. Note down this number on the input box to the right.

Step 2
Now Your Bust Measurement

Lean forward about 45 degrees and loosely wrap the measuring tape around the fullest part of your bust. Note down this number on the input box to the right. For most accurate results, measure without a bra.


We recommend checking the following for the right fit:

1. The bra band should stay put without being uncomfortably tight.
2. Shoulder straps shouldn’t dig in, slip off, or cut into your armpits.
3. Your breasts should be contained in the cups without overflow or gaps.
4. The underwire should contour your breasts without poking anywhere.
5. Generally, the center gore should lie flat against your chest. However, if your breasts are touching when supported (there is no room for the center gore between your breasts), you are wearing a wireless bra with no center gore, or you have an inverted sternum, the center gore doesn’t need to lie flat against your chest.

At the end of the day, your own comfort is your #1 guide.

Measure tighter if: your bra band tends to ride up in the back and gets pushed down in front (the “seesaw effect”), the straps are too far apart and cut into your armpit, or you prefer a firm fit.

Measure looser if: you have ribcage sensitivities, you have a more muscular body type, you only want nipple coverage with minimal support, or you prefer a relaxed fit.

Understance uses US sizing. If you are more familiar with UK
sizing, here’s a side-by-side comparison of cup sizes: