How to Measure for a Bra
Finding a well-fitting bra can be a challenge, but taking accurate measurements is the first and most important step. This calculator uses a common method to estimate your bra size, but remember that sizes can vary between brands. Always try on a bra before purchasing.
Step 1: Measure Your Band Size
Using a soft measuring tape, measure around your rib cage, directly under your bust where the bra band would sit. Make sure the tape is level and snug, but not too tight. This is your underbust measurement.
To get your band size, if the measurement is an even number, add 4 inches. If it's an odd number, add 5 inches. This is a traditional method; some modern methods suggest rounding to the nearest even number. Our calculator uses the traditional "+4/+5" method.
Step 2: Measure Your Bust Size
Measure around the fullest part of your bust. The tape should be level and not too tight. It's best to do this while wearing a non-padded bra or no bra at all.
Step 3: Calculate Your Cup Size
Subtract your calculated band size (from Step 1) from your bust measurement (from Step 2). The difference in inches determines your cup size:
- 0" difference = AA cup
- 1" difference = A cup
- 2" difference = B cup
- 3" difference = C cup
- 4" difference = D cup
- 5" difference = DD cup
- And so on...
What are Sister Sizes? If a bra in your calculated size doesn't fit quite right, try a "sister size." This means going up one band size and down one cup size (e.g., from 34C to 36B), or down one band size and up one cup size (e.g., from 34C to 32D). The calculator provides these for you.