Not Sure About Your Bra Size?
Finding the right bra size isn’t always as simple as picking the same size you bought last time.
Your measurements can change, and sizing labels are not always the same between countries or brands.
Our Bra Size Calculator gives you an easy way to estimate your size using your bust and underbust measurements.
Simply enter the information requested by the calculator and check your estimated band and cup size.
You can use the result as a starting point when shopping for bras online or checking different sizing systems.
A good fit is about more than a number on a label, so it’s always worth checking how a bra feels when you wear it.
Bra Size Calculator
Estimate a starting bra size from snug underbust and bust measurements. Brand sizing and fit can vary considerably.
How to Use the Bra Size Calculator
Before starting, take a flexible measuring tape.
- Choose the measurement unit requested by the calculator.
- Measure your underbust as instructed.
- Measure around the fullest part of your bust.
- Enter both measurements carefully.
- Select the available sizing system, if the calculator provides one.
- Click Calculate to see your estimated bra size.
For a better estimate, take your measurements without wearing a padded bra.
How to Measure Your Underbust
Wrap the measuring tape around your ribcage, directly underneath your bust.
Keep the tape level around your body. It should feel comfortably snug without pressing too tightly against your skin.
How to Measure Your Bust
Measure around the fullest part of your bust.
Keep the tape level across your back and make sure it isn’t too tight or too loose.
Try to stand naturally while measuring.
Understanding Band and Cup Size
A bra size generally contains two parts:
Band Size: This relates to the measurement around your ribcage, underneath your bust.
Cup Size: This is determined using the difference between bust and underbust measurements according to the relevant sizing system.
Different countries and brands can use different sizing rules, so the same label does not always mean the same fit everywhere.
Why Can Bra Sizes Differ Between Brands?
A few things can affect how a bra fits:
- Different sizing charts.
- Differences in cup shape.
- Different band construction.
- Stretch and fabric materials.
- Personal comfort and fit preferences.
The calculator gives an estimated size, not a guarantee that every bra in that size will fit.
Frequently Asked Questions
How do I calculate my bra size at home?
Measure your underbust and the fullest part of your bust, then enter the values into the calculator.
What is the difference between band size and cup size?
Band size relates to the ribcage measurement, while cup size is calculated using the difference between bust and underbust measurements.
Are US and UK bra sizes the same?
No. The sizing systems can use different cup-size progressions and labels.
Can I convert my bra size into EU sizing?
You can use the calculator’s supported sizing options, but always check the brand’s own chart as sizing conventions may vary.
Why does my bra feel uncomfortable even when the size seems correct?
Cup shape, strap adjustment, band fit and individual brand design can all affect comfort.
How often should I measure my bra size?
Rechecking your measurements when your body changes or when your current bras no longer fit comfortably can be helpful.
A Helpful Reminder
Use this calculator as a starting point. A proper fitting check and the brand’s sizing guide are still important when choosing a bra.