How to Measure Your Bra Size
Finding your bra size at home takes two measurements and about five minutes: your underbust (directly under the bust) and your bust (around the fullest part). All you need is a soft measuring tape. Follow the four steps below, then enter your numbers into the calculator.
Measure your underbust
Wrap the tape directly under your bust, where a bra band would sit. Keep it snug and level all the way around, and breathe out normally — don't hold your breath. Write down the number.
Measure your bust
Wrap the tape around the fullest part of your bust. Keep it level across your back — use a mirror to check — and don't pull it tight. It should lie flat without digging in. Write down the number.
Enter your measurements
Type your underbust and bust numbers into the bra size calculator and choose your country. The calculator works out the band size and cup letter for you.
Check your estimated size
You'll get an estimated size such as 34C. Remember that this is a starting point: sizing varies by brand and style, so compare the result with the manufacturer's own size chart and consider sister sizes.
Measuring Tips
- Measure in an unlined, non-padded bra — or without one — so padding doesn't add extra volume.
- Breathe normally and stand relaxed; don't hold your breath or puff out your chest.
- Keep the tape level all the way around your body; check in a mirror.
- Ask someone to help if you can — it's easier to keep the tape straight.
- Write your numbers down in inches or centimeters before you calculate.
- Re-measure if your weight changes, or about once a year.
Ready to calculate?
Enter your two measurements and get your estimated bra size in seconds.
Frequently Asked Questions
What do I need to measure my bra size at home?
You only need a soft measuring tape and a mirror. The calculator on this site accepts inches or centimeters, so use whichever unit your tape shows.
Should I wear a bra while taking my measurements?
Measure in an unlined, non-padded bra — or without a bra — because padding adds volume and can distort your bust measurement.
Why is my calculated size different from the size I usually wear?
Bra sizing is not standardized, so the same labeled size can fit differently between brands and styles. Treat the result as a starting point and compare it with each brand's own size chart.
How often should I re-measure?
Re-measure whenever your weight changes noticeably, and otherwise about once a year, since band and bust measurements can shift over time.
What should I do if my measurements fall between two sizes?
Try the nearest size first, and consider sister sizes — for example, if a 34C band feels tight, a 36B keeps a similar cup volume with a looser band. Our sister size calculator can show your options.