How do you measure for a bra?

a woman uses a measuring tape to measure the circumference of her bust.

If you’ve ever worn a bra that’s the wrong size, you’ll know it can have a big impact on your day-to-day life. If you haven’t, you might wonder if it’s worth getting the right size – after all, not many people are likely to see your underwear on a daily basis. However, an ill-fitting bra can cause bigger problems than a simple fashion faux pas. They can leave red marks on your skin if too tight, force you to keep pulling the straps back up if they’re too big, and even leave you with back pain. One way to help make sure you get the right size bra the next time you shop is to measure yourself.

How to measure your bra size

If taking your own measurements sounds complicated, don’t worry. It’s easy to measure your own bra size – and even easier if you have someone on hand to help you. But it’s important to be aware that your measurements are only part of the puzzle. Different styles of bras can fit differently, so you may need to experiment with a variety of styles before you find the one that’s best for you. If there’s a style you know and love, you can also stick to that one!

Either way, taking your measurements will make sure you get the right size and lessen the risk of your bra not fitting you properly. A bra size – such as 36D, for example – is made up of two parts. The number, in this case 36, refers to the band size, or the circumference of your chest. The letter, on the other hand, refers to the cup size, starting from A and getting bigger as the alphabet goes on.

How to measure bra band size

In order to measure your band size, you’ll need a flexible tape measure – preferably one that measures in inches. The number of your bra size refers to the circumference of the underband of your bra – i.e. the bit that goes around your rib cage, under your breasts and clips together at the back (or the front, in front-fastening bras) to secure the bra in place.

To find this number, you’ll need to measure the circumference of your ribcage at the spot where the band would sit. It’s easiest to do this while wearing a bra you already have that fits well. Make sure the measuring tape is snug to your body – we’ll add a bit of wiggle room in a moment. If you have someone on hand, ask them to check that the measuring tape is straight all the way around. If not, use a mirror to help.

Take the tape measure away, and add three inches to the number you got. This gives you a little breathing room which can be altered to suit your personal preferences by using the different sets of hooks on the band to tighten or loosen the bra as needed.

Top tip! Bras almost always come in even number sizes. If your measurements give you an odd number, opt for the next size up rather than sizing down.

How to measure cup size

To get down into the nitty gritty details of the matter, cup size isn’t actually a measurement of volume as you might expect. In reality, it represents the difference between two measurements – the underbust circumference which you just measured to find the band size, and the circumference of the fullest part of your bust.

The scale starts at AA, which is where there are no inches of difference between the two measurements. Going on, each inch of difference takes you to the next cup size – but it’s not quite as simple as working your way through the alphabet.

Some sizes have single letters and others double letters – but each one is a full size on its own, not a half size. For example, if the difference between your two measurements is eight inches, your cup size should be FF or double F. Here is how the sizing goes:

  • AA
  • A
  • B
  • C
  • D
  • DD
  • E
  • F
  • FF
  • G
  • GG
  • H
  • H

And this isn’t the end of the scale. If you need a larger cup size, the scale continues with I, J, JJ, K, L, LL and M cups.

So how do you measure it? Well, you already have your underbust size from measuring the band size – please note for this measurement you’ll need the original number you measured on the tape, not the one with three extra inches added or the one you rounded up to get an even number. Now you’ll measure again using the same method, but a little higher, at the fullest part of your bust. Again, check to make sure the tape is snug and straight before noting down the measurement in inches.

Then, simply take the band measurement away from the bust measurement to find the difference. The corresponding letter will be your cup size – put it together with the band size from above and you’ll be well on your way to getting a great-fitting bra.

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