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.
- Coverage and centre height are construction variables.
- The same nominal size can behave differently across styles.
Step-by-step method
- 1
Identify whether your goal is coverage, neckline access or centre comfort.
- 2
Compare cup-edge height and centre height.
- 3
Check whether strap position changes under the intended top/dress.
- 4
Fit-check the new construction rather than copying the old result.
- 5
Keep the size label as a starting point, not proof of equivalence.
Worked example
Example: someone whose bra shows above a deep V neckline may need a plunge construction, while someone seeking more overall containment may compare a fuller-coverage cup.
Common mistakes that change the answer
- Treating “full cup” as a promise of one exact coverage percentage.
- Assuming a plunge always gives less support.
- Ignoring band fit because the neckline changed.
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.