A well-fitting bra should feel supportive and comfortable, but finding your starting size can be confusing. A soft measuring tape and a few minutes at home can help you narrow down the options. Measurements are a guide, not a guarantee: sizing can vary between brands and styles.
What you need
Use a soft measuring tape and a mirror if helpful. Wear a non-padded bra or measure without one, whichever helps you get a consistent measurement. Keep the tape level and breathe normally. You can measure in centimetres or inches, but use the same unit for both measurements.
1. Measure under your bust
Wrap the tape around your ribcage directly beneath your bust. It should sit snugly and level without digging in. Write down the number. This is your underbust measurement and helps you find a starting band size on the brand's size chart.
2. Measure around the fullest part of your bust
Place the tape around the fullest part of your bust, keeping it level across your back. Let it rest gently against your body without compressing the tissue. Write down this number too.
3. Check the size chart for the bra you want
Compare both measurements with the size chart provided for the specific brand or product. Avoid assuming the same number and letter will fit identically in every style. If you are between sizes, check the product's fit notes and return or exchange policy before choosing.
Try the fit, not just the label
Fasten a new bra on a comfortable hook. The band should stay level around your body and feel snug without discomfort. The cups should contain your bust without obvious gaping or spilling, and straps should stay in place without carrying all the support. Move around a little and notice how it feels when you sit, stand and raise your arms.
If the first size does not feel right
Try a nearby size or a different style. A change in band size can affect which cup size feels right, so use the brand's chart rather than guessing from the letter alone. Your preferred fit may also change with different fabrics, cuts and outfits.
Your measurements are a helpful place to begin. The best bra size is the one that fits you comfortably in the style you choose.