Calculate Your Bra Size
Enter two measurements to get an estimated starting size.
Your Estimated US Bra Size
How Your Size Was Estimated
What Does Your Size Mean?
The number represents the band-size category around your ribcage.
The cup letter is related to the difference between bust and band measurements.
Try a Sister Size
Nearby sizes may offer a different band fit with a similar cup volume.
Sister sizes are starting points, not guaranteed fit equivalents.
International Bra Size Converter
Already know your US size? Select your band and cup to see approximate equivalents in other sizing systems.
International conversions vary by manufacturer. Treat the results as approximate and check the relevant brand's own size chart.
How to Measure Your Bra Size
Measure Your Underbust
Place the measuring tape around your ribcage directly below your bust. Keep it level and comfortably snug. Record the measurement in inches or centimeters.
Measure Your Full Bust
Measure around the fullest part of your bust. Keep the tape level without pulling it tight or compressing the breast tissue.
Enter Both Measurements
Choose one measurement unit, enter both values, and select Calculate My Bra Size. The result is an estimate rather than a guaranteed fit.
US Bra Size Chart
Browse band and cup combinations. The chart lists size labels, not the exact body measurements required by every brand.
Cup labels and available sizes vary among manufacturers. This reference is a general starting point.
Does Your Bra Fit Properly?
A calculator can suggest a starting size, but it cannot assess how a particular bra fits your body. Check these points when trying one on.
The Band Stays Level
The band should remain reasonably level around your torso instead of riding up your back. It should feel secure without painful pressure.
The Cups Fit Smoothly
Look for persistent gaps, pinching, or breast tissue spilling over the cup edges. Different cup shapes can fit differently even in the same labeled size.
The Straps Feel Comfortable
Straps should stay in place without digging painfully into your shoulders. Strap tension alone does not determine the correct size.
Free Printable Bra Size Chart
Use the chart above as a reference. You can print it or save it as a PDF from your browser. The CSV option lets you save the size matrix as data.
Frequently Asked Questions
How accurate is an online bra size calculator?
It provides a starting estimate based on the measurements and calculation method used. Bra style, body shape, and manufacturer sizing can affect the actual fit.
Does a C cup have the same volume in every band size?
No. Cup volume is related to band size. A 30C and a 36C do not represent identical cup volumes.
Are US and UK bra sizes the same?
Not always. Band labels often correspond, but cup-letter sequences can differ, particularly at larger cup sizes. Check the brand's conversion chart when buying a bra.
What are sister sizes?
Sister sizes are nearby band-and-cup combinations intended to have a similar cup volume. They can be useful when assessing fit, but they are not guaranteed to feel the same.
Should I add four inches to my underbust measurement?
Different sizing methods use different rules. This calculator uses a simplified nearest-even-band estimate and does not add four inches. Always compare the result with the sizing method recommended by your chosen brand.
Can I save or print my results?
Yes. Use Print / Save Results as PDF and choose Save as PDF in your browser's print window. You can also download a text summary.