Universal Bra Size Calculator
Estimate a starting bra size from body measurements and compare common US, UK, EU, and AU size labels. Results are a sizing reference, not a medical assessment.
How this starting point is calculated
BraSizePRO uses the snug underbust and standing bust measurements as the two inputs for the main calculation. Tight underbust and leaning bust are optional references and do not change the result.
- Band: snug underbust is converted to inches, rounded to the nearest whole inch, then moved to the next even number when needed.
- Cup index: standing bust minus snug underbust is rounded to the nearest whole inch.
- Label: the cup index is looked up in the selected US, UK, EU, or AU cup sequence.
- Conversion: common regional band labels come from the same canonical sizing data used by the calculator.
This is a reproducible sizing reference, not a universal fit guarantee. Manufacturer charts, garment construction, cup shape, fabric stretch, body shape, and fit preferences can change the size that works in a particular bra. See the full sizing methodology.
Frequently Asked Questions
Answers about sizing methods, measurements, and fit considerations.
Why is my calculated size different from the size I usually buy?
Bra sizing is not uniform across brands. This calculator provides a measurement-based starting point; use the target brand's own size chart before purchasing.
What is the difference between US and UK cup sizes?
Cup-letter progressions differ between sizing systems, especially at larger cup ranges. The calculator shows the selected system and common conversions as reference values.
How should I take the measurements?
Use a flexible tape measure and follow the measurement instructions shown in the calculator. Keep the tape level and record the measurements consistently.