Bra Size Calculator
Estimate your UK bra size from two measurements.
Estimated UK bra size
30E
- Band size
- 30 in
- Cup difference
- 6 in
Estimate only — sizing varies between brands.
v1.0 · Reviewed September 2026
How this is worked out
The underbust measurement is converted to inches and rounded to the nearest even number for the band. The cup comes from the difference between bust and underbust in inches, with one inch per cup step.
Worked example
- Underbust 76 cm
- Bust 90 cm
76 cm is about 30 inches, and the 14 cm difference is about 6 inches
30E
Assumptions and limits
- UK cup lettering, which runs A, B, C, D, DD, E, F, FF, G, GG, H, HH, J. American and European systems label the same cups differently.
- An estimate only. Sizing varies between brands and styles, so treat this as a starting point for trying sizes on.
- Measure the underbust snugly and the bust loosely, wearing a non-padded bra.