Bra Size Calculator
Find your perfect bra fit with our easy calculator. Supports US, UK, and European sizing standards based on your band and bust measurements.
📏 How to Measure
About Bra Sizing
Finding the right bra size can be tricky because different brands use different sizing methods. This calculator uses the True-to-Size method (often called the "ABTF" method), which matches your band size closer to your actual ribcage measurement, providing better support than outdated methods that add 4 inches to the band.
Signs of a Poor Fit
- Band Rides Up: The band is too loose. Try a smaller band size and larger cup (Sister Size Down).
- Straps Dig In: The band is too loose, forcing straps to carry the weight. Support should come 80% from the band.
- Cups Gaping: Cups are too large or the shape is wrong for your breast tissue.
- Spilling Over (Quadboob): Cups are too small. Try a larger cup size.
Sister Sizes
Sister sizes are bras with the same cup volume but different band lengths. For example, if a 34C is too loose in the band, a 32D has the same cup volume but a tighter band.
? Frequently Asked Questions
Many stores use the '+4 method' (adding 4 inches to your underbust) which often results in a band that is too loose and cups that are too small. Our calculator uses your actual measurements for a supportive fit.
Yes, though sports bras often run tighter. You might prefer your 'Sister Size Up' (larger band, smaller cup) for comfort during exercise.
It is recommended to measure yourself every 6 months, or after any significant weight change or pregnancy.