Measuring your bra size at home isn’t complicated, but precision is key. With just a soft measuring tape and ten minutes of your time, you can find a comfortable starting point for your bra-shopping journey.
What You Need
- A soft, flexible measuring tape (often used for sewing).
- An unpadded, well-fitting bra (or measure without one if you prefer).
- A mirror (to ensure the tape remains level).
Step 1: The Underbust Measurement
Your underbust measurement determines your band size, which provides 80% of a bra’s support.
- How to do it: Wrap the tape around your ribcage, directly beneath your bust where the bra band normally sits. Make sure the tape is parallel to the ground all the way around.
- How tight? Pull the tape so it feels snug—about as tight as you would want a bra band to feel.
- The Math: Take the measurement in inches. If you are using modern +0 sizing (which we recommend), round to the nearest even number. That is your band size!
Why +0? Older sizing methods often tell you to add 4 or 5 inches to this measurement. This dates back to the 1930s when materials had no stretch. Today’s elastic bands are designed to stretch to your exact measurement.
Step 2: The Overbust Measurement
This measurement, combined with your band size, determines your cup volume.
- How to do it: Wrap the tape around the fullest part of your bust (usually across the nipples). Again, check the mirror to ensure it’s parallel to the floor.
- How tight? Keep the tape somewhat loose. It should rest lightly against your skin without compressing tissue.
Step 3: Determining the Cup Size
Your cup size is simply the difference between your Overbust and your Band Size.
- Example: If your Band Size is 34 and your Overbust is 37 inches.
- Difference: 37 - 34 = 3 inches.
- Result: A 3-inch difference typically corresponds to a ‘C’ cup.
Your starting size is 34C.
Remember: It’s Just a Starting Point
Just like jeans or shoes, every brand of lingerie runs slightly differently. Use your calculated size as a baseline. When you go shopping, you may find that in one brand you’re a 34C, but in another a 36B fits better. Don’t be afraid to try on sister sizes!