Bra Size Calculator
Enter two measurements, get your band and cup size instantly — free, private, no sign-up.
Bra Size Calculator
Measure directly under your bust, tape snug and level.
Measure around the fullest part of your bust, tape level, wearing a non-padded bra.
How to measure for a bra size
Band: wrap the tape directly under your bust, where the band of a bra would sit. Keep it snug and level all the way around, parallel to the floor.
Bust: wrap the tape around the fullest part of your bust — usually across the nipple line — while wearing a non-padded bra or no bra at all. Keep the tape level, not pulled tight.
The difference between your bust and band measurement determines your cup size — a bigger gap means a bigger cup letter.
Why the same size can feel different across brands
Bra sizing has less global standardization than almost any other garment category. Two brands' "34B" can differ meaningfully in actual volume and band tightness. Our calculator gives you a strong, standard-method starting point — see our Women's Size Chart for the international band-to-region conversion table, or read our guide on why brands size differently.
Frequently asked
Should I measure over or under clothing? Measure directly on skin or over a thin, non-padded bra for the most accurate result.
My band and cup don't match what I usually buy — why? Brand-to-brand variation is normal in bra sizing. Use this as a starting point and adjust based on your own experience with a specific brand.
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