How to use the Bra Size Calculator
The bra size calculator estimates band and cup size from your underbust and bust measurements.
Open the Bra Size Calculator →
What you need to enter
- Underbust (inches, snug)
- Bust at fullest point (inches)
The formula
Band = underbust rounded to the nearest even number. Cup = bust − band, in inches (1 = A, 2 = B, 3 = C…).
Worked example
Using the default values in the calculator:
- Underbust (inches, snug): 32
- Bust at fullest point (inches): 36
| Estimated size | 32D |
| Band | 32 |
| Cup difference | 4 in |
| EU band (cm) | 80 |
Tips for better results
- Measure in a non-padded bra.
- Try sister sizes.
Common mistakes to avoid
- Pulling the tape too tight.
- Assuming every brand fits the same.
Please note: Results are estimates for general use. For safety-critical work such as electrical or building projects, check with a qualified professional and local codes. See our Disclaimer.