How to Measure Your Bra Size at Home: Step-by-Step Fit Guide

Quick answer

Measure your band size by wrapping a soft tape snugly around your ribcage directly under your bust, then add four inches if the number is even or five if it is odd. Measure your bust at the fullest point, subtract the band number from the bust number, and use the difference to find your cup: one inch equals A, two inches equals B, three inches equals C, and so on. Re-measure on a second day to confirm, then test the size in a real bra before buying.

What you need before you start

A soft measuring tape, a mirror, and a non-padded bra are enough for an accurate at-home measurement. Wear the bra if you have one that fits reasonably well; if not, measure without a bra but keep your arms relaxed at your sides. Stand in front of a mirror so you can see whether the tape stays level all the way around your back. A tape that dips or twists will give you a band size that is too large or too small.

How to measure your band size

Wrap the tape around your ribcage, directly under your bust, keeping it parallel to the floor. Pull it snug, but not tight enough to compress your ribs. Breathe out normally and read the number where the tape meets. If the measurement is an even number, add four inches; if it is odd, add five. This gives your starting band size. For example, a 30-inch ribcage measurement becomes a 34 band. If you are between sizes, round down for a firmer fit or up for more comfort, then adjust the cup accordingly.

How to measure your bust and find your cup size

Wrap the tape around the fullest part of your bust, usually across the nipple line. Keep the tape level and relaxed, not pulling tight. Write down the number. Subtract your band size from your bust measurement. The difference in inches tells you your cup: 1 inch is an A, 2 inches is a B, 3 inches is a C, 4 inches is a D, 5 inches is a DD/E, and so on. If the difference falls between two cups, try the smaller cup first if the band feels loose, or the larger cup if the band feels snug.

Check the fit with a real bra

Numbers are a starting point, not a final verdict. Try on a bra in your calculated size and check three things: the band should sit level and firm around your ribcage, the center gore should lie flat against your sternum, and the cups should contain your breast tissue without gaping or spilling. If the band rides up in the back, go down a band size and up a cup size. If the cups wrinkle, go down a cup size. Half-cup and full-cup styles can feel different even in the same size because of how they distribute volume, so test the specific shape you plan to wear.

When to re-measure

Re-measure every six to twelve months, or after any change in weight, exercise routine, or hormonal cycle. A bra that fit perfectly last year may not fit now. If you are shopping for a special occasion or a new style, measure again rather than relying on an old number. Keep your measurements written down so you can compare when trying new brands.

Five steps to your bra size

1. Step 1: Measure your ribcage: Wrap a soft tape snugly around your ribcage directly under your bust, keeping it level. Read the number in inches. Common mistake: letting the tape sag in the back. Check in a mirror.
2. Step 2: Calculate your band size: If your ribcage measurement is even, add four inches. If it is odd, add five inches. This is your band size. Checkpoint: the band number should feel firm but not tight when you try it on.
3. Step 3: Measure your bust: Wrap the tape around the fullest part of your bust, keeping it level and relaxed. Write down the number. Common mistake: pulling the tape tight. It should rest on your skin without compressing.
4. Step 4: Find your cup size: Subtract your band size from your bust measurement. 1 inch = A, 2 inches = B, 3 inches = C, 4 inches = D, 5 inches = DD/E. If the difference is between sizes, try the smaller cup with a looser band or the larger cup with a firmer band.
5. Step 5: Test the fit: Try on a bra in your calculated size. The band should be level, the center gore flat, and the cups smooth without gaping or spilling. Next step: adjust band or cup by one size until all three checkpoints pass.

How real styles apply these measurements

• Velvet Memories Half cup: The Velvet Memories Half cup bra features a teardrop opening between the cups and rounded arabesques across the bust, with velvet Lycra straps. The half-cup shape is designed for open necklines and works best when your band measurement is accurate, so the cups sit flat and the arabesque detail stays visible.
• Art of Ink Half cup bra Symphonie Bleue: The Art of Ink Half cup bra Symphonie Bleue has vertical seaming to create a push-up cleavage, with a rhinestone gem between the cups and a double strap at the back. Vertical seaming and a push-up effect rely on a firm band and a correct cup size; if your band is too loose, the lift will not hold.