How to Choose the Right Bra Size

Written by Lauren Payne, 1st February 2023

If your bra isn’t comfy, it’s possibly the wrong size. Lovehoney’s experts share their tips for how to measure your bra size and how to know what bra size you are.

Raise your hand if you're the proud owner of boobs? If you raised your hand, then I’m sure you’ve asked yourself ‘What bra size am I?’, or googled ‘How to figure out what bra size you are’ at least once in your life. So now, we need to ask, do you actually know what your bra size is?

Given that most people gain or lose weight over time, very few people remain the same size and shape forever. Chances are, your bra size has changed a lot since the last time you went shopping for a sexy lingerie set, and you may not have even noticed!

Up to 90% of women walk around wearing the wrong size bra, which is totally crazy if you ask us! Not to be too damn scary, but this seemingly innocent problem can lead to a number of serious health problems, including:

  • headaches
  • backaches
  • shoulder and neck pain
  • blocked lymph nodes
  • skin abrasions
  • breast pain

It’s incredibly important that you know what your perfect bra size is - not only so you feel comfortable and able to move around in your balcony bra but also so you can feel sexy as hell when you pull out your cheeky peekaboo bra.

So, when did you last get measured? When did you last measure yourself? If the answer to both of those questions is ‘I have absolutely no idea’, then don’t worry gals, we’re here to help.

It’s a good idea to check your bra size at least once a year. You don’t need a professional lingerista to burst into your house, thrusting a tape measure at your chesticles, all you need to know is how to measure bra size so you can do it yourself, simply and easily.

Video: How to Check the Fit of Your Bra

Discover how to measure bra size to discover the right bra size for you.

Measuring your Bra size

Find a soft tape measure that’s long enough to wrap around your body, and a mirror so you’re able to gaze at your beautiful self.

Then grab your favourite bra and slip into it. Generally, if you have a bra that you wear almost every day of the week and is also incredibly comfortable, then that’s probably the bra that fits you best and is your perfect size.

However, you should always make sure that your fave bra doesn't have any extra padding. Padding can affect your measurements and lead to you stocking up on a bunch of bras that actually don’t fit you properly. So if your best bosom buddy has a bit of extra padding, just remove it from the cups of your bra before you start measuring.

Measuring your underbust

Your underbust sits underneath your brilliant boobs and goes from the middle of your chest to the centre of your spine. This is usually where your bra band sits and where pesky underwire can dig into your skin if you’re wearing a push-up bra, or an underbust corset that’s a bit too small.

Your underbust size can also be known as your accurate band size. This would be your chest size if your sweater puppies weren’t hanging around.

To measure your underbust, stand in front of the mirror wearing your coziest bra and loop the measuring tape around your back.

Pull the measuring tape firmly (but not too tight!) against your skin and place it just beneath your boobsicles.

Check the measurement in inches, as well as centimetres. Australia is a metric country after all, and so, depending on what kind of bra you’re hoping to add to your lingerie drawer, you may need to have your underbust measurements in both inches, and centimetres, ready to go.

If you check your underbust measurement and it’s an odd number, round it up to the next even number, as bra sizes tend to only come in even numbers. Also, if your underbust measurement isn’t a full number, we suggest rounding it up. Some lingerie brands do carry half sizes, but not all of them do, so it’s best to round your measurement up to a full number if you discover your underbust is between sizes.

Once you’ve done that you’ll have your perfect underbust size and will be able to avoid any tight underwire digging into you when you’re showing off your new lacy lingerie.

Measuring your overbust

Now it’s time to measure your overbust, which is the fullest part of your bust and probably better known as your boob area (chest plus breasts!).

To measure your overbust, move the tape measure up to the fullest part of your bust, hold it against your lady lumps, and wrap it around your body without digging the measuring tape into your skin. It’s important here to not press the measuring tape too tightly over your breasts.

The aim here is to discover how big your boobs are, so pressing them down with the measuring tape would kind of defeat the purpose. We already know your chest measurements without your boobs, now we need to know your measurements with your boobs added in!

To get your perfect overbust measurements, remember to read your measurement in both inches and centimetres, to cover both bases. Again, if your overbust measurement isn’t a full number, round it up to the next full number, and if your measurements are odd numbers, round them up to the nearest even number.

Finding out your cup size

Now this is where we get to switch things up a bit. Toss the measuring tape and crack out the pencil ‘cuz it's time to do a little bit of maths.

It can obviously be a bit tricky to wrap a measuring tape around your precious melons, so to find out what your perfect cup size is, all you have to do is subtract your underbust measurement from your overbust measurement. Every inch (or centimetre) difference between the underbust and overbust measurements equals an extra cup size.

Remember when we said your underbust measurement would be your chest measurement if your boobs weren’t around? Well, to find out your cups size, really all we’re doing is flipping things around and figuring out what your boob size would be if your torso wasn’t attached to them.

For example, if you measure 36 inches under the bust (your underbust size), and 40 inches around your bust (your overbust size), you’re then left with a size difference of 4 inches.

Cup sizes range from A - H, and each letter represents an inch of breast space. So, 4 inches would then be four sizes up from size A, which is the size DD. That would then make you a 36DD in regular bra sizing.

Most women have one boob that’s slightly larger than the other and if you’re breasts are fraternal twins instead of identical twin sisters, then you may be wondering how you can find your perfect cup size when your bosom buddies aren’t exactly the same.

Well, luckily, when it comes to measuring your breasticles, you’ll more than likely find the perfect bra size for your larger breast and will just need to add a little extra padding to the cup of your smaller breast to ensure it gets all of the support it deserves.

Of course, if you’re looking to buy a peekaboo bra that doesn’t have a cup, or an open cup bra set, then the cup size of your bra probably won’t be something you’d be worrying too much about.

Measuring for non-cup sized bras

Speaking of bras without cup sizes, sometimes, you may come across bras, bralettes and corsets (particularly in sets) that are sized by dress size, rather than cup sizes. You may also come across bras have their own unique sizing system that may not include double lettering, which can make shopping for bras and lacy lingerie a little confusing.

At Lovehoney, all of these particular types of bras will have a brand size chart featured on the product page that can help you find out what your perfect size is. Whether you need to translate your regular bra size into small, medium, or large, or see if your boobs are considered E’s instead of DD’s, the brand size chart should be able to help you find the perfect fit.

Video: Sister Sizing Explained

Lovehoney experts share their tips for how to understand sister sizing by filling a bra with chocolate. It has to be seen to be believed, but it will help you understand breast volume and curb your chocolate addiction.

Sister sizes

If you’re trying on a particular bra and you’ve discovered that your regular size just isn’t quite right, then it might be time to whip out something we like to call your sister size.

Sister sizes are a way to calculate alternate bra sizes from your usual size. It’s based on the fundamental idea that the volume of boob that a bra can contain is proportional to the underbust size.

This means that when you increase the underbust size, you're also increasing the size of the cup, even if you choose the same cup size.

Sister sizes can be incredibly helpful when you’re shopping for bras that don’t follow the usual bra sizing conventions and go by dress size instead of bra size. They can also help you when the size of your new dream bra runs a bit smaller (or larger) than your usual go-to bra.

Really your sister sizes are just like actual sisters, helping you navigate the world of bras and understand how your boobsicles fit into each different style.

Say you are a 34B. If you increase the underbust size of your bra to the next width up, which would be a 36 and decrease the cup by one size to an A, then you have what is known as one of your sister sizes.

This is a bra with essentially the same volume as your true size. In this example, your bra of 34B would fit you, but so would the 36A. By going up a band size and down a cup size, you have kept the overall bra volume the same.

Generally speaking, you can go up to two sister sizes in either direction. If you take things too far, though, you could end up with a bra that may fit your underbust perfectly but also have a couple of saggy cups that are way too big for your boobs - and no one wants that!

Shop with confidence

Now you know how to measure for a bra and know what size of bra your bodacious breasts need to feel comfortable, supported and downright sexy, you’ll be able to shop for some amazing lingerie without any unwanted headaches, backaches and skin abrasions coming into the picture. How amazing is that?!

You can confidently buy yourself a plum bra set that comes with a crotchless G-string, or maybe even try a front-fastening longline bra for a sweet change of pace. You could treat yourself to a pink bralette with delicate jewel detailing, or a fierce leather-look longline push-up bra to keep your boobs feeling extra secure.

No matter what style you’ve got your eye on, now that your know your perfect bra size, you’ll be able to dive headfirst into the world of lingerie and find something that makes you feel incredible.

Check out our guide to lingerie styles to get the full low down on the different types of lingerie you can choose from, and see if a white lingerie set is something you’d like to slip your bosom buddies into.

Just make sure to check in with yourself again in another year to make sure that your perfect bra size still actually is your perfect bra size. It’s better to be safe than sorry, right?!

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