Sizes vary between manufacturers. Check 2–3 different bras to see if she is consistently the same size.
Buy something she actually likes to ensure she feels confident and comfortable. Tips for How to Buy Lingerie for Your Wife That She'll Love how to buy a bra for your wife
Do not rely on memory; keep a note in your phone of her band size (the number) and cup size (the letter). Sizes vary between manufacturers
If she cuts out her tags, try asking her best friend—they often know or can find out discreetly. Step 2: Identify Her Style how to buy a bra for your wife