Bra Size Calculator
Find Your Perfect Fit
Enter your measurements below to calculate your ideal bra size. For the most accurate results, use a soft measuring tape and follow our measuring guide.
How to Measure
Underbust / Band Size Measurement
- Wrap the measuring tape directly under your bust, where your bra band would sit
- Keep the tape parallel to the ground
- Breathe normally and take the measurement on a normal exhale
- The tape should be snug but not digging into your skin
Bust Size Measurement
- Wrap the measuring tape around your back and across the fullest part of your bust
- Ensure the tape is parallel to the ground
- The tape should be snug but not compressing your breast tissue
- If you're currently wearing a bra, make sure it's not a padded or push-up style for accurate measurement
Measuring Tips
- Use a soft fabric measuring tape for the most accurate results
- Stand straight with your arms relaxed by your sides when taking measurements
- For the most accurate results, have someone help you take the measurements
- If you don't have a measuring tape, you can use a string and then measure it against a ruler
Bra Sizing Guide
Cup Size Chart
| Bust-Underbust Difference | US Size | UK Size | EU Size | AU/NZ Size |
|---|---|---|---|---|
| 1 inch (2.5 cm) | A | A | A | A |
| 2 inches (5 cm) | B | B | B | B |
| 3 inches (7.5 cm) | C | C | C | C |
| 4 inches (10 cm) | D | D | D | D |
| 5 inches (12.5 cm) | DD/E | DD | E | DD |
| 6 inches (15 cm) | DDD/F | E | F | E |
| 7 inches (17.5 cm) | G | F | G | F |
| 8 inches (20 cm) | H | FF | H | G |
Common Fitting Issues
Band rides up in the back
This indicates your band is too loose. Try a smaller band size and larger cup size to keep the same volume.
Cup spillage
If your breasts are spilling out of the cups, you need a larger cup size.
Gapping in the cups
If there's empty space in the cups, you may need a smaller cup size or a different cup style.
Center gore doesn't lay flat
If the center piece doesn't touch your sternum, you likely need a larger cup size.
Important Note
Bra sizing is not standardized across brands. Your size may vary depending on the brand and style. This calculator provides a starting point for finding your perfect fit.
About Bra Sizes
Understanding Sister Sizes
Sister sizes have the same cup volume but on different band sizes. If your calculated size doesn't feel comfortable, you can try a sister size:
- For a looser band: Go up one band size and down one cup size (e.g., 34C → 36B)
- For a tighter band: Go down one band size and up one cup size (e.g., 34C → 32D)
Signs of a Good Fit
The band is snug on the loosest hook and stays horizontal around your body
The center gore (the piece between the cups) lies flat against your sternum
The cups fully contain your breast tissue with no spillage or gapping
The straps stay in place without digging into your shoulders
Our calculator provides an estimation of your bra size. For the most accurate fit, we recommend getting professionally fitted when possible.