Sister Size Bra Chart

Sister sizes are groups of bra sizes that share the same cup volume but with different band sizes. When you go up a band size, you go down a cup size (and vice versa). For example, 32D, 34C, and 36B are sister sizes — they all hold the same cup volume.

Try a sister size when your current bra band feels too tight or too loose, but the cups fit well. If the band is too tight, go up one band size and down one cup. If it's too loose, go down one band and up one cup.

Sister sizes maintain the same cup volume, but the fit will differ slightly. A tighter band with a larger cup will feel more supported. A looser band with a smaller cup will feel more relaxed. The overall coverage and shape of the cup may also differ.