Buying lingerie online without trying it on can feel intimidating, but with a few minutes and a soft measuring tape, you can find your true size with confidence. This guide walks you through the exact same measurements our team uses when sizing pieces for our Fancy Sinner subscribers. 

 
Grab a flexible measuring tape, a non-padded bra (or no bra), and a mirror. Measure in front of a mirror so you can keep the tape level, and stand naturally, don't suck in or push your chest forward.
 

 
Wrap the tape around your ribcage, directly under your bust. Pull it snug but not tight. Round to the nearest whole inch (or centimeter). If you measure 32, your band size is 32. Some bra brands add 4–5 inches; we don't. Measure exactly.
 

 
Wrap the tape around the fullest part of your bust, keeping it parallel to the floor. The difference between your bust and band measurements determines your cup: 1 inch = A, 2 = B, 3 = C, 4 = D, 5 = DD, 6 = E.
 

 
Stand with your feet together and wrap the tape around the fullest part of your hips, usually 7–9 inches below your natural waist. This is your panty size.
 

 
Bralettes don't follow standard band/cup sizing. Use your underbust measurement and your bust measurement to pick S/M/L/XL according to the size chart on each product page. When in doubt, size up. Bralettes are designed for comfort.
 

 
The most common mistake is wearing a band that's too loose. The band should sit firm and horizontal across your back, not ride up. If your straps are doing all the work, your band is too big. The second most common mistake: cup spillage means you need a larger cup, not a smaller band.
 
Still unsure? Send us a message and we'll offer a free virtual fitting for every Fancy Sinner subscriber.