Bra Size Calculator for Perfect Fit and Comfort

A bra size has two parts: the band size (the number) and the cup size (the letter). Both need to fit well so you feel good all day.

Cup Size Chart

How to Measure Your Bra Size at Home

All you need is a soft tape measure. This takes just a few minutes and it makes a big difference. Many women skip this step and end up wearing the wrong size for years — so it is worth doing properly.

• 1 Wear a Simple Bra Put on a thin, non-padded bra. No thick padding — it can add extra bulk and change the numbers. A simple bra or even just a thin top works best.
• 2 Measure Under Your Breasts (Band Size) Wrap the tape measure around your body, just under your breasts. Keep it straight and level all the way around. This number in inches is your band size. If you get an odd number like 31, round it up to 32.
• 3 Measure Around the Fullest Part of Your Bust Now wrap the tape around the biggest part of your chest. Do not pull it tight — just let it sit gently. Stand up straight while doing this. Write this number down too.
• 4 Find Your Cup Size Take the bust number and minus the band number. The gap between the two tells you your cup size. Use the chart above to find your letter.
• 5 Put Both Together Put the band number and cup letter together. That is your bra size. For example — band is 34, bust is 37, gap is 3 inches = C cup. So your size is 34C.

How Do Bra Sizes Work?

Once you have your size, it helps to know what the number and letter really mean. A lot of people think their size is fixed — but in real life, fit can change from one bra brand to the next. Think of your size as a starting point, not a final answer.

Sister Sizing — A Simple Trick

Sister sizing helps when your bra almost fits but not quite. If the band feels too tight, go up one number and down one letter. If the band feels too loose, go down one number and up one letter. The cup space stays about the same.

So a 34C, a 32D, and a 36B all have the same amount of space inside the cup. This is very handy when the cup feels fine but the band is the problem.

How to Pick the Right Bra Size for You

Getting the right size is not just about the numbers — it is about how the bra feels on your body all day long. A bra that fits well should feel easy and comfortable from morning to night. You should not even notice it is there.

• 1 Check the Band First The band should sit flat and steady around your chest. You should be able to slide two fingers under it easily. If the band rides up at the back, it is too loose. Go down one size.
• 2 Look at the Straps The straps should stay in place without digging into your shoulders. They are only there to give a little lift — the band does the main job. If your straps leave red marks, your band is probably too loose and the straps are doing too much work.
• 3 Check the Cups The cups should fully cover your breasts with no gaps and no overflow. The middle part of the bra (between the cups) should lie flat against your chest. If it pokes out, the cup is too small. If the cup has loose fabric, it is too big.
• 4 Move Around in It Lift your arms, bend forward, walk around. A good bra stays in place when you move. If anything slides, pokes, or digs in — try a different size or style.

When the band, straps, and cups all feel right at the same time — that is your size. Even a small change like going up one cup or down one band size can make a big difference in how comfortable you feel.

Signs Your Bra Does Not Fit Right

Most women wear the wrong bra size — studies say it is somewhere between 70 and 85 out of every 100 women. This happens because bra sizes are not the same in every country or every brand. The same size from two different shops can feel very different.

One of the biggest mistakes is wearing a band that is too big and a cup that is too small. This gives you less support and more discomfort. Over time it can cause shoulder pain, neck pain, and sore marks on your skin.

• The band goes up at the back — the band is too loose; try going down one number
• The straps dig in or keep falling off — the band is not doing its job; the straps are carrying too much weight
• Your breasts spill over the top or sides — the cup is too small; go up one letter
• The cups have wrinkles or loose fabric — the cup is too big; go down one letter
• The middle part does not lie flat — the cup is too small or the style is not right for your shape
• Red marks on your skin when you take it off — the band or wires are too tight
• The underwire pokes or hurts — the cup is too small or the shape is not right for you
• You feel uncomfortable all day — a bra that fits well should feel fine from morning to night

Why Does Breast Tissue Come Out of the Sides of My Cups?

This is very common and usually just means the bra is not sitting right on your body. It can happen if your breasts sit slightly to the sides, which is totally normal.

A simple fix is to use your hands to guide your breasts into the cups. Lean forward a little, then reach into each cup and gently scoop your breast forward and up into the cup. This is called “scoop and swoop” and fitters in shops do this all the time. Once everything is in place, the bra will feel and look much better.

What Bra Style Works Best for My Shape?

Your size is only part of the story. The shape of your breasts also matters when picking a bra. Different styles work better for different shapes. Knowing your shape can help you find a bra that feels great and looks smooth under your clothes.