Women's Bra & Lingerie Size Chart: How to Measure at Home

To find your bra size, measure directly under your bust for your band size and around the fullest part of your bust for your bust measurement, then use the difference between the two to work out your cup. Match both numbers to a size chart to get your starting size, keeping in mind that Australian bra sizing uses even dress size band numbers (8, 10, 12, 14 and so on) rather than the direct centimetre or inch numbers used overseas.

This guide walks through the at-home measuring process step by step, gives you an Australian bra size chart to match your measurements against, explains sister sizing, and covers what to do if your size still doesn't feel right.

How to Measure Your Bra Size at Home

You'll need a soft fabric tape measure, the kind used for sewing. A rigid ruler or metal tape won't sit properly against your body and will throw the result off.

• 1. Wear a non-padded bra, or no bra at all. Padded cups and moulded shells add extra volume to your bust measurement and can shift your result by a cup size or more.

• 2. Measure your band (underbust). Wrap the tape directly under your bust, where a bra band would sit, keeping it level and parallel to the floor all the way around. Pull it snug, but not so tight that it digs in. Round to the nearest whole number.

• 3. Measure your bust (overbust). Wrap the tape around the fullest part of your bust, again keeping it level and parallel to the floor. The tape should sit comfortably, loose enough that you could slip a finger underneath.

• 4. Work out your cup size. Subtract your band measurement from your bust measurement. In inches, a difference of 1 inch is roughly an A cup, 2 inches a B, 3 inches a C, 4 inches a D, and so on up the alphabet. In centimetres, each cup step is roughly 2.5cm.

• 5. Match your band and cup to a size chart to get your starting size, then compare it against the specific brand's own chart before you buy, since sizing varies between brands even when the numbers look the same.

On the measuring method itself, older bra fitting guidance often added four or five inches to your underbust to calculate the band size. Many fit specialists have moved away from this over time, since it tends to produce an oversized band, particularly for people outside an average frame. Most current guidance instead uses your direct, snug underbust measurement as the band starting point, which is the method used above.

Common Measuring Mistakes to Avoid

A few small errors account for most inaccurate results:

• Measuring over a padded or moulded bra. This adds false volume to your bust measurement and can push your cup calculation up by a full letter or more.

• Letting the tape sag at the back. If the tape measure isn't level all the way around, both your band and bust readings will be off, usually reading smaller than they actually are.

• Pulling the tape too tight. A snug fit is correct, but compressing the skin gives you a number smaller than your real measurement.

• Measuring while slouching or leaning forward. Stand naturally with your arms relaxed at your sides for both measurements, since posture shifts the bust reading noticeably.

• Rounding in the wrong direction. If your underbust measurement sits between two even numbers, it's worth trying both nearby bands rather than always rounding up or down the same way.

Bra Band Size Chart (Australian Sizing)

Australian bra bands are dress size numbers, not a direct centimetre reading, which is where a lot of the confusion comes from. Use your underbust measurement in centimetres to find your starting AU band below.

These ranges are a general guide rather than a fixed rule, since brands round and grade their bands slightly differently. If your measurement falls right on the edge of two rows, it's worth trying both.

Bra Cup Size Chart

Once you have your band size, use the difference between your bust and band measurements to find your cup. Australian cup letters follow the same sequence as UK sizing.

Put your band and cup together and you have your starting Australian size, for example AU 12C or AU 14DD. From here, always check the individual product's own size chart, since fabric, cup shape and construction can shift the fit even within the same labelled size.

International Size Conversion At a Glance

If you're shopping a UK, US or European brand, the band number usually changes even when your actual size hasn't. As a quick reference:

• AU to UK: the cup letter stays the same. Just convert the band, for example AU 12 to UK 34, AU 14 to UK 36.

• AU to US: bands convert the same way as UK (AU 12 to US 34), but cup letters diverge above D. A UK/AU DD is usually a US DD, while a UK/AU E is often a US DDD.

• AU to EU: European bands are in centimetres and cup letters run one step ahead of AU above D, so a UK/AU DD is often a European E.

Because the cup lettering shifts more than the band once you're above a D cup, it's worth double checking both numbers rather than converting the band alone. For the full breakdown across UK, US, EU, France and more, see our international size conversion chart, which goes into more detail than we have room for here.

Understanding Sister Sizing

Sister sizing is different from international conversion. It's what you try when your actual size is out of stock, or when the band and cup don't feel right together.

The rule: if you go down a band size, go up a cup size to keep roughly the same cup volume, and vice versa. So if your measured size is AU 14C but the band feels loose, AU 12D is your sister size on the tighter side. If the band feels snug, AU 16B is the looser option with the same cup volume. Sister sizing doesn't replace measuring, but it's a useful tool once you know your starting size and want to fine-tune the fit.

Signs Your Bra Size Might Be Wrong

A few common signs suggest it's time to remeasure, regardless of what your current label says:

• The band rides up at the back instead of sitting level.

• The straps dig in or slip off your shoulders during the day.

• The underwire pokes at the sides or sits on breast tissue rather than your ribcage.

• The centre gore doesn't sit flat against your sternum.

• There's visible spillage at the top or sides of the cup, or the cup gapes and wrinkles.

If more than one of these sounds familiar, it's worth working through the fit systematically rather than guessing at a new size. Our fit troubleshooting guide covers each of these issues in more depth.

Extended and Plus Size Bra Ranges

Cup sizing doesn't stop at D or DD. Many Australian and UK brands extend through F, FF, G and beyond, and band sizes commonly go up to AU 20 or further in specialist ranges. If you're not sure where "plus size" actually starts in lingerie, our guide on what's considered plus size in lingerie explains how the terminology works and where brands typically draw the line.

For a full walkthrough on shopping extended sizing, including what design details matter most in a well made larger bra, see our plus size lingerie guide.

Sizing Other Lingerie: Underwear, Bodysuits and Shapewear

Bra sizing runs on its own band and cup system, but most other lingerie in Australia, briefs, bikinis, bodysuits and shapewear, follows the standard AU/NZ dress size scale (8, 10, 12, 14 and up), based on your waist and hip measurements rather than your bust. As a general rule, if you wear an AU 12 in dresses, an AU 12 brief is a reasonable starting point, though cut and fabric stretch will shift this slightly from style to style.

Fit matters just as much here as it does for bras. If briefs or thongs are uncomfortable no matter what size you try, the issue is sometimes the cut rather than the size, our guide on why thongs feel uncomfortable walks through the most common causes and fixes.

Measuring for Bodysuits and Shapewear

Bodysuits and shapewear add another layer of complexity, since they combine a bra style top with a bottom section, and both need to fit at once. For the bust portion, use the same band and cup measurements you'd use for a bra. For the body of the piece, your waist and hip measurements (matched to the standard AU dress size scale) matter more than your bust alone, since a bodysuit needs to move with your torso through the day rather than just sit at the bust.

Shapewear specifically is usually sized by hip measurement rather than waist, since a snug hip fit is what gives shapewear its smoothing effect without it rolling or digging in. If you're between two sizes in a shapewear chart, sizing up is generally the safer choice, since overly tight shapewear can be uncomfortable to wear for a full day and doesn't actually smooth any better than a correctly fitted size.

How Often Should You Remeasure?

Your size isn't fixed for life. Weight changes, pregnancy, breastfeeding, and even changes in your regular exercise can all shift your band and cup measurements. A reasonable habit is to remeasure roughly every six months, and always after a significant weight change or a new bra that doesn't feel right despite being your usual size.

Frequently Asked Questions

How do I know if I'm measuring correctly?

Use a soft tape measure, keep it level and parallel to the floor for both measurements, and measure without a padded bra. If your band measurement feels loose enough to pull away from your body by more than a couple of centimetres, it's too big. If it leaves marks or is hard to breathe in, it's too small.

Why do I seem to be a different size in every brand?

Bra sizing isn't standardised across brands or countries. The same measurements can produce a different recommended size depending on the brand's own charts and construction. Always check the specific product's size chart rather than assuming your size carries across from one label to another.

Is a bra size chart accurate for every style?

It's a starting point rather than a guarantee. Balconette, plunge, and moulded styles can all fit differently at the same labelled size because the cup shape and coverage vary. Use the chart to narrow down your size, then check reviews or size specific notes on the individual product where available.

Do I need to be remeasured professionally?

Not necessarily. An accurate at-home measurement with a soft tape is enough for most people to find a solid starting size. A professional or in-store fitting can help if you've tried several sizes at home and still aren't landing on a comfortable fit.

Can my bra size be different in each breast?

Yes, this is common and completely normal. Most people have some natural difference in size between breasts. If the difference is significant, fit to the larger side and consider a bra with removable padding or inserts to fill out the smaller cup, rather than sizing down and risking discomfort on the larger side.

Should I size up if I'm between two sizes?

It depends on which measurement is borderline. If your band measurement sits between two sizes, try the smaller band with the next cup size up as your first option, since bands stretch slightly with wear while cups generally don't. If it's your cup that's borderline, trust the size that gives full coverage without gaping.

Once you know your numbers, you're ready to shop with more confidence across the whole range, from everyday bras to going-out pieces. Head back to our complete women's lingerie style guide to explore what's available in your size, or go straight to our all women collection to start shopping now.