Check band, cups, centre and straps as separate fit variables; different constructions redistribute support differently.
Cup letters are relational
A cup letter does not describe one absolute volume independent of the band and sizing convention.
- Band and cup must be converted separately.
- FR/ES band labels are not the same as EU band labels.
Step-by-step method
- 1
Confirm the source size is actually an EU label, not FR/ES.
- 2
Convert the EU band to the UK/US inch-based band convention.
- 3
Locate the cup within the EU progression.
- 4
Map that cup step to the UK progression rather than copying the same letter blindly.
- 5
Check the destination brand chart and real fit before buying.
Worked example
Example: an EU 75 band corresponds to a UK/US 34 band convention; the cup label still needs its own step-by-step conversion.
Common mistakes that change the answer
- Confusing EU 75 with FR/ES 90, which are different band labels for a related range.
- Keeping the same cup letter across systems without checking progression.
- Assuming two converted labels guarantee identical cup shape.
When the related tool helps
Use the calculator after you have confirmed the measurement method or product-specific chart. Arithmetic can be exact while the fit or care decision still depends on construction, brand rules or your personal reference garment.
Continue with the working tool
The related tool starts with blank inputs and keeps its assumptions visible.
Open related tool →Questions people ask
Is there one universal answer for every brand?
No. Use the method to narrow the decision, then verify the current product chart and construction.
What should I do if two clues conflict?
Prioritize direct measurement and observable fit, change one variable at a time, and compare the adjacent size or construction rather than forcing a generic rule.