Two Steps Away.
Still the Same Volume.
A cousin size takes the sister-size logic two steps further same cup volume, but on a band two sizes up or down. Useful when even the nearest sister size isn't available, or a style only runs in select bands.
- ✓ Results in under a minute, no sign-up needed
- ✓ Shows cousin down and cousin up
- ✓ Pairs well with our Sister Size Calculator
Find your cousin sizes
Select your current band and cup size.
Sister Size vs. Cousin Size
A sister size moves one band size in either direction while adjusting the cup by one letter to keep volume constant. A cousin size repeats that step twice two bands over, two cup letters adjusted which keeps the same underlying volume but changes the band fit even more. Cousin sizes are less precise than sister sizes and best used only when nothing closer is available.
Frequently Asked Questions
Is a cousin size as reliable as a sister size?
It's a reasonable approximation, but less precise the band fit changes more, so try it on if you can before relying on it.
When would I actually need a cousin size?
Mainly when a style is discontinued in your size and its immediate sister size, but still available further out.
Should I check sister size first?
Yes always try the nearest sister size before moving to a cousin size, since it's the closer, more reliable match.