Getting an accurate bra measurement is the foundation of finding comfortable, supportive lingerie that fits perfectly. While professional fittings are excellent, many Australian women prefer the convenience and privacy of measuring at home. With the right technique and a few simple tools, you can achieve professional-quality measurements without leaving your bedroom.
The importance of accurate measurements cannot be overstated. Studies consistently show that approximately 80% of women wear the wrong bra size, often resulting in discomfort, poor posture, and inadequate support. By learning the correct measuring technique, you can join the minority of women who enjoy properly fitting bras every day.
What You'll Need for Accurate Measurements
Before you begin, gather these essential items to ensure the most accurate results. First, you'll need a soft, flexible measuring tape—the kind used for sewing is ideal. Avoid using a metal tape measure, as it won't conform to your body's curves and can give inaccurate readings.
You'll also want access to a mirror, preferably a full-length one, so you can verify that the measuring tape stays parallel to the floor throughout the process. Finally, consider wearing a well-fitting, non-padded bra during measurement. If you don't have one that fits well, measuring without a bra is perfectly acceptable and often provides more accurate results.
Step 1: Measuring Your Underbust
The underbust measurement determines your band size, which is the number in your bra size (such as 10, 12, 14 in Australian sizing). This measurement is crucial because the band provides approximately 80% of your bra's support.
Stand in front of your mirror and wrap the measuring tape around your ribcage, directly beneath your breasts. The tape should sit horizontally—check in the mirror to ensure it hasn't slipped up or down at the back. Pull the tape snug against your skin, but not so tight that it digs in or restricts your breathing. You should be able to fit one finger comfortably between the tape and your skin.
Breathe normally and take the measurement at the end of a natural exhale. Record this number in centimetres if you're using our Australian bra size calculator, or in inches if you prefer imperial measurements. Take this measurement three times and use the average to account for any slight variations.
Step 2: Measuring Your Bust
The bust measurement, combined with your underbust measurement, determines your cup size. This measurement captures the fullest part of your bust and is equally important for achieving a proper fit.
Position the measuring tape around the fullest part of your bust, typically at nipple level. Again, use your mirror to confirm the tape remains parallel to the floor all the way around. The tape should rest gently against your skin without compressing the breast tissue—think of it as a light touch rather than a firm grip.
Lean forward slightly at a 45-degree angle when taking this measurement. This position allows your breast tissue to fall naturally forward, giving you the most accurate representation of your bust volume. Many women skip this step and end up with a cup size that's too small because their breast tissue wasn't properly accounted for.
Step 3: Understanding Your Measurements
Once you have both measurements, the difference between them determines your cup size. In the Australian sizing system, each 2-centimetre difference corresponds to one cup size. For example, if your underbust measures 78cm and your bust measures 92cm, the 14cm difference indicates approximately a D cup.
However, calculating this manually can be confusing, especially when dealing with the nuances of the Australian sizing system. This is why we created our free bra size calculator—simply enter your two measurements, and it instantly provides your Australian bra size along with international conversions for UK, US, and EU sizing.
Common Measurement Mistakes to Avoid
Even with clear instructions, certain mistakes can throw off your measurements. One of the most common errors is measuring over a padded bra. Padding adds volume to your bust measurement, potentially resulting in a cup size that's too large. Always measure over an unpadded bra or no bra at all.
Another frequent mistake is pulling the tape too tight during the underbust measurement. While you want a snug fit, excessive tightness leads to a band size that's too small, which can cause the band to ride up, dig into your skin, and fail to provide adequate support.
Measuring at the wrong time of day or month can also affect your results. Breast size naturally fluctuates due to hormonal changes throughout your menstrual cycle. For the most representative measurement, measure in the morning when water retention is typically at its lowest, and try to measure at the same point in your cycle each time.
When to Re-Measure Your Bra Size
Your bra size isn't static—it changes throughout your life in response to various factors. Weight changes of more than a few kilograms often affect bra size, sometimes significantly. Hormonal changes during pregnancy, breastfeeding, and menopause can also alter your measurements considerably.
We recommend re-measuring your bra size every six to twelve months, or whenever you notice signs that your current bras no longer fit properly. These signs include straps that constantly slip, bands that ride up your back, cups that gap or overflow, or underwires that poke or don't sit flat against your ribcage.
Putting Your Measurements to Use
Now that you have accurate measurements, it's time to find your perfect size. Use our free Australian bra size calculator to instantly convert your measurements into your bra size. Our tool accounts for the unique Australian sizing system and provides equivalent sizes for international shopping.
Remember that your calculated size is a starting point, not an absolute rule. Different brands, styles, and materials can affect how a particular bra fits. Armed with your accurate measurements, you're now equipped to try on bras with confidence, knowing you're in the right size range for your body.