Bra Size Calculator

Find your bra size using underbust and bust measurements (US sizing)

Your Bra Size
Band Size
Cup Size
Bust - Underbust
Band SizeUnderbust (in)Cup SizeDifference (in)
2826–27AA< 1
3028–29A1
3230–31B2
3432–33C3
3634–35D4
3836–37DD (E)5
4038–39DDD (F)6
4240–41G7
4442–43H8

About the Bra Size Calculator

This bra size calculator uses your underbust and bust measurements to determine your band size, cup size, and recommended bra size following US sizing conventions. Accurate measurements are key to finding a comfortable and supportive fit.

How It Works

Band Size = rounded underbust (even)  |  Cup Size = difference (bust - band) mapped to letter

Frequently Asked Questions

How should I measure my underbust and bust?

Measure underbust snugly around the ribcage directly under the bust. Measure bust around the fullest part of the chest, keeping the tape parallel to the ground. Wear a non-padded bra for the most accurate bust measurement. Take measurements while standing and breathing normally.

Why does the band size sometimes feel different from calculated?

Bra fit varies by brand, fabric, and body shape. The calculator provides a starting point, but sister sizing (adjusting band and cup proportionally) may improve fit. For example, a 34C is sister-sized to 32D or 36B. Always try bras on and assess comfort.