Bra Size Calculator
Estimate your bra size using two simple measurements. Enter your underbust and fullest bust measurements to calculate an estimated band and cup size.
Enter Your Measurements
For the most useful estimate, use a soft measuring tape and measure while wearing a lightly lined or non-padded bra.
Your Result Will Appear Here
Add your underbust and bust measurements, select your preferred sizing system, and calculate your estimated bra size.
How the Bra Size Calculator Works
The calculator uses your underbust measurement to estimate band size and the difference between your bust and band measurements to estimate cup size.
Measure Your Underbust
Wrap a measuring tape directly beneath your bust. Keep it level and comfortably snug around your ribcage.
Measure Your Full Bust
Measure around the fullest part of your bust without pulling the tape too tightly or allowing it to sag.
Calculate Your Size
The calculator estimates your band and cup size and also provides nearby sister sizes you may want to try.
How to Measure for a Bra
Accurate measurements give the calculator a better starting point. A flexible measuring tape works best.
Underbust Measurement
Position the tape directly underneath your bust. Keep it parallel to the floor and snug enough that it does not slide down.
Full Bust Measurement
Wrap the tape around the fullest part of your bust. Keep your posture natural and avoid compressing the breast tissue.
Measure More Than Once
Taking each measurement two or three times can help reduce small measurement errors.
What Makes a Bra Fit Properly?
Measurements provide a useful starting point, but several fit details can help you determine whether a bra actually suits your body.
Supportive Band
The band should sit level around your torso and feel secure without being painfully tight or riding up your back.
Comfortable Cups
Breast tissue should sit comfortably inside the cups without significant spilling, gaps, or excessive compression.
Correct Strap Tension
Straps should remain comfortably in place without digging into the shoulders or carrying all of the bra's support.
Bra Size Calculator FAQs
Helpful answers about bra measurements, sizing and choosing the right fit.
Measure your snug underbust and the fullest part of your bust. Your underbust helps estimate the band size, while the difference between the bust and band measurements is used to estimate the cup size.
It provides a useful starting estimate based on commonly used sizing methods. Actual fit can vary between brands, bra designs and individual body shapes.
Either is fine. Select the measurement unit you prefer before entering your numbers. The calculator automatically converts centimeters when necessary.
Bra sizing is not perfectly standardized. Different brands may use slightly different patterns, cup depths, band stretch and sizing conventions.
Sister sizes use a different band and cup letter while keeping approximately similar cup volume. For example, moving up one band size normally means moving down one cup size.
It is useful to measure again whenever your current bras no longer fit comfortably or after significant body changes. Even without noticeable changes, checking your measurements occasionally can help maintain a better fit.