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How to accurately measure your bra size at home in 4 simple steps

What’s your bra size? 32A, 34C, 38DD? Absolutely no idea? Haven't bothered finding out since 2012? We hear you. Whatever size you think your bra size is, there’s a pretty good chance you’re wrong. Sorry. Ask any bra fitter and they’ll be sure to tell you the majority of women leave with a different sized bra to the one they've been wearing for the past three years. In fact, according to studies, around 70%-81% of us do.

If like over half of the nation, you haven't bothered to have a professional bra fitting in several years, or are too shy to ask for help from the professionals — after all getting you bra size measured can be quite intimidating — don't worry, we get it. It's likely you've been busy making the most of the three minutes of summer weather we've had, so naturally for most of us, bra fitting hasn't exactly been at the top of our 'to do list'.

We've called on the bra fitting experts at Ann Summers to break down exactly how to measure yourself for a bra in the comfort of your own home so you have absolutely no excuse for wearing the wrong size.

Why do you need a well-fitted bra?

While the wrong bra may not seem like a big deal, it can cause some real physical problems that can been rectified in a few minutes. Bras that are too tight can damage breast tissue and even cause breathing difficulties. Inadequate support can lead to longer term problems such as neck, shoulder and back pain, as well as pinched nerves.

You’re also more likely get longer term problems like poor posture and premature sagging, which can feel unpleasant. According to experts, with around 4cm range of sway in every direction, very gentle movement while using the wrong bra could be enough to stretch your delicate skin. Gemma Birtwistle, Design and Creative Manager at lingerie brand Gossard tell us: “The cups of your bra should contain your breast without spillage. The wires should sit at the centre and underarm flat against your body. Wearing the correct size bra can help with posture, as your bra underband should support the redistribution of the breast weight particularly in those with a heavy bust.”

How often should you get your bra size measure?

Women's bodies change pre and post puberty. Breasts on another hand can fluctuate size and change as often and as drastically as this unpredictable British weather — be that from weight changes or hormonal changes, particularly during pregnancy, but through period cycles, contraceptive pills etc. For that reason, you should have a bra fitting every 6-12 months to ensure that you are wearing the right fit bra all year round.

How to measure your bra size

“If you’re suffering from any of these bra issues, it’s definitely time to check those measurements. Heading to a professional fitter really is the best way to go. Not only can they measure you up, but they can also advise on the most flattering shape and style,” said the Ann Summers fitter.

To get started, all you'll need is a full-length mirror, a soft tape measure and your top off, although make sure you're wearing a comfortable but unpadded bra and stand up straight while you're taking measurements.

Measure band size: Measure around your ribcage, just below where your bra fits. This is your band measurement.

Measure bust size: Measure around your back and the fullest part of your breasts. Top tip: use your nipples as guidance. This is your bust measurement.

Find the final figures: Round both measurements to the nearest whole number.

Calculate cup size: To calculate your cup size subtract your band size (as referenced in step one) from your bust size (as referenced in step two). Every inch difference is a cup size up e.g. one inch equals A, two inches equals B, three inches equals C, and so on.

Now before you think that you’re all done, you’re not. While this gives you an approximate bra size, it won’t necessarily be totally accurate. That’s because boobs also vary in shape – which is totally normal, by the way.

How to find the perfect fit

While a tape measure can tell you the right size in terms of numbers, it’s not always the key to finding the perfect fit. The only way to truly get your size spot on is through good old trial and error. Once you have a bra on, you’ll be able to tell if it fits in all the right places, providing the perfect level of support.

How to find your bra size without a measuring tape

Although measuring your bust size using an actual tape measurer is relatively a pretty accurate way to determine your bra size, there are a few other ways to estimate your bra size if you don't have a measuring tape lying around.

Use a string or ribbon

Find a string or ribbon and wrap it around your ribcage, just under your bust. Make sure it's snug but not too tight. Mark where the two ends of the string meet and measure the length with a ruler. This measurement is your band size. Then, wrap the same string around the fullest part of your bust and mark where the ends meet again. Measure the length and subtract your band measurement from it. The difference between the two measurements will give you a rough estimate of your cup size. For example, if your band measurement is 32 inches and your bust measurement is 35 inches, the difference is three inches, corresponding to a C cup.

Use your current bra size as a reference

If you already have a bra that fits well, you can also use its size as a reference. Bare in mind that different brands may have slightly different sizing, so this method may not always be sound proof. To find it, try looking at the tag inside the bra and if necessary, use a bra size conversion chart to translate it to a different sizing system.

Look at how your current bra fits

If you're currently wearing a bra that doesn't fit well, it might be a bit difficult to determine your correct size. However, you can still try and ‘guestimate’ your bra size using it, as of your bra is visibly too small or too large in certain areas, it can give you a general idea of what size should fit your bust best. For example, if your cups are overflowing, you may need a larger cup size. Depending if band is riding up your back or its on the looser side, you may need a bigger or smaller band size.

While these methods can give you a rough estimate of your bra size, keep in mind that they may not be as accurate as simply measuring with a soft tape measure. If possible, it's best to get measured by a bra expert at a lingerie store or simply find yourself a measuring tape to ensure you're getting the most accurate fit.

How should your bra sit?

The band

First up, the band itself. This should sit firm and straight. You should also be able to get two fingers under it but feel a little resistance. If it’s too loose, you need a smaller size. If you’re struggling to get your fingers in, then you should try the next size up. When buying a bra, try the band in its loosest setting, it a better reflection of how the fit is. Remember, after prolonged use, bands stretch.

The straps

The straps are a key part of your bra. You’ll be forgiven for thinking that the tighter the straps the more support they provide, but they should actually sit comfortably on the shoulder without any pinching or sliding. Be sure to check they are equal on both sides.

The centre

Also known as the ‘bra bridge’, this is the little bit of fabric nestled snuggly between your boobs. It should sit flat to your body without any room underneath but also not digging into your skin. If you can see a gap, you need to go up in size.

The wires

If you’re testing out a bra with wiring, be sure to check it fits properly. These should follow the natural curve at the base of your breast. If they’re sitting on it or too far below, they won’t do their job and this is where a large amount of support comes from.

The cups

If all the other elements are adjusted correctly, your cups should be smooth and perfectly moulded to the line curve of your breast. Remember the warning signs we mentioned above: spot any wrinkles or sagging? Then move on.

How to check your bra sister-size

Finding out your bra sister-size is a great hack if you're shopping across different brands or can't find the exact bra size in the style you want. Often women can fit comfortably in their bra size and their sister bra size. Just like clothes, bra sizes are not always universal, and fluctuate from brand to brand, but if you shop around the sizer sizes you should be able to easily find your match wherever you decide to shop.

A sister size is essentially the bra size that gives you the same cup volume but with a smaller or larger band size. Some people like a little more wiggle room around the band, while others like it a bit more snug, play around with the your sister size. Although it's worth noting that experts usually recommend keeping the band snug when you first purchase as it's the first part of the bra that will stretch.

How to check if you need a new bra

Fabric stretches, and therefore so do bras, so using an old bra is not an accurate way of measuring your cup size or judging if you need re-measurement. They start to lose shape at around the six to nine months mark as the elastic fibres in the band and straps begin to deteriorate. So that may mean that it's time you need to start thinking about getting a new bra. Although, with gentle care and reduce use (by rotating use of your bra-drobe), then your bras can last a lot longer.

How to find the right bra for your breast shape

There are a couple of ways to find the right bra for your breast shape. Granted it may mostly be out of personal choice, here are some ways to narrow down your bra selection for maximum comfort and support.

Breasts come in all different shapes and sizes but experts have narrowed down breast shapes to seven categories. These include round, east west, side set (widely set), teardrop, narrow, asymmetrical and bell shape. Different bras can comfortably fit different breast shapes so take note and shop accordingly, (more on that further down).

Gemma Birtwistle says: “A new bra will feel firm but should never hurt. If the straps feel uncomfortable, try loosening them, but not enough that they fall off your shoulders. When a bra fits correctly, the underband will firmly hold your breasts in place and elevate the bust, the wire should never sit on your breast tissue. If the wires are uncomfortable, you are likely wearing the incorrect cup size. To help with comfort give a new bra a light wash before wearing, it will soften the components providing maximum comfort.”

Also take into consideration the materials used: wiring, strap width and length, fabric, constructions, and just general style.

There will be some trial and error involved but here are some bra styles to consider for your breast shape.

Full and round

Full and round breasts are equally full at the top and bottom. While most styles work well for this shape, full coverage plunge bras are comforting and compliment rounder breast shapes well.


Wide-set or side set breasts are shaped with breast tissue laying at the sides, there is often a larger gap between the breasts which exposes more of your chest or ribcage area. For this shape a plunge bra with a lower centre and a wider band with side support would work best.


Teardrop shaped breasts are round, with the bottoms slightly wider than the tops. Teardrop shaped breast may not require as much lift so most underwire styles, such as balconette, full coverage, push up and bralette would work.


Asymmetric breasts usually have one breast noticeably bigger than the other. You're better off sizing to the larger breast, and then opting for a side shaper on the smaller side for maximum comfort. Stretch lace bras, which are bras that have an elastic paneling along the top and bottom of the bra are a great option for asymmetrical breasts.

Bell shape

Bell shaped breasts usually appear larger and fuller at the bottom, and slimmer at the top. Bell shape breasts are usually found in people who have more breast tissue, so we recommend plunge style bras or a full coverage bra with stretch lace.

This article was originally published on Glamour UK.

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