How do bra measurements and sizes work? This makes no sense to me

What Are Sister Bra Sizes?

How does one understand bra measurements? - Quora

How does one understand bra measurements? - Quora

Bras: What is Sister Sizing? Bra Sizing Explained by Kimmay

A guide to pattern cup sizes (and a handy reference)

Finally, Bra Sizes Explained – Understanding How Bra And Cup Sizes

What cup size would I be if I am a 32D/34C? I want to buy 'strapless bras' but the sizes are only for cup size, not band. - Quora

How to Measure Your Bra Size: Bra Band and Cup Measurement Chart

How to Measure Bra Size – Bra Size Calculator & Chart

How does a size 32A bra and a 32B bra differ? - Quora

What is a plunge bra? - Quora

Bra Fit Guide: Find Your Perfect Bra

Sister Sizes, Bra Fit Guide & Size Charts

Is 34B a small, large, or average bra size for a 49 year old? - Quora

I do not know which bra cup is suitable for me, my under burst is 40 inches and my upper burst is 47 inches, so what bra size is best for me? - Quora