How to Determine Bra Size

X

This article is co-authored by a team of editors and trained researchers who confirm the accuracy and completeness of the article.

The wikiHow Content Management team carefully monitors the work of editors to ensure that every article is up to a high standard of quality.

This article has been viewed 99,928 times.

It’s hard to believe that 80% of women wear the wrong bra size! Most people wear bras that are too big on the back and too tight on the breasts. While sizing can vary slightly between brands, they all follow a basic size system that you can use to determine your bra size at home.

Table of Contents

Basic knowledge of bra size

The cup of the bust is not an absolute constant. Here’s what a lot of people think about bra sizes: D cups look the same for all bust sizes, or small breasts automatically mean you have an A cup. Actually, cup sizes change proportions. according to bust size – that is, it depends on the size of bust. For example, a 32D cup will have a smaller holding volume than a 36D cup, but both are D cups.

How will a well-fitting bra help you feel and look? There are a number of signs that indicate if a bra is right for you. Here’s what to look out for when measuring your bust or trying on different bra sizes:

Tight-fit bra anklet: The leg loop, not the strap, is primarily responsible for supporting the breasts. You can only insert one or a maximum of two fingers under the anklet.
Full coverage of the breasts: A well-fitting bra will not let your breasts show out on the sides and under the armpits. For underwire bras, you can measure side coverage by the underwire: if the top of the underwire points towards the center of your armpits, the bra fits you well.
The center belt lies flat: The center belt (the part of the shirt around and between the cups) should lie flat on the chest without rubbing against the skin causing discomfort. If you don’t have this, then you have chosen the wrong bra.
Smooth curves: Avoid creating a “four-breasted” image because the cup is so small that its top grinds against the breast tissue that rests on the bra. A well-fitting bra should create a smooth image without dividing the breast tissue.

Notice the different breast shapes. What if you’ve found the right bra size but it still doesn’t fit? Perhaps you chose the wrong bra model for your bust shape. Apply the following solutions to the problem of breast shape:

Wide breasts: If the breast tissue is spread over a wide area and has little protrusion, you have wide breasts. (Another sign to look out for: there’s breast tissue near your collarbone regardless of how small your breasts are.) Horizontal cup bras are best suited for people with wide breasts, with the cup opening at the top in a horizontal cut. Avoid wearing V-cup bras.
Bell chest: The base of the chest is relatively small but the breast tissue is quite heavy, don’t be disappointed with this bust shape! You should choose a bra with a bust, two separate bra cups and can provide more coverage. Avoid wearing a cropped bra or a V-cup.

Know about bra sizes. If you find a bra that’s almost perfect but isn’t quite, try on its sister size. The two bras are sister sizes, meaning their difference is just enough to compensate for the difference between different brands.

One size down: Reduces bust size by two units but increases cup size by one. For example, you drop from 36 C to 34 D.
One size up: Increase bust size by two units but decrease cup size by one. For example, you go from 36 C to 38 B.

Learn bra measurements. There are currently two different bra measurements (shown below). Modern gauges are more commonly used, but some manufacturers still use traditional gauges. Unfortunately, it’s hard to tell which manufacturer (or brand) uses which gauge. Here’s how to reduce your risk:

If you’re trying on bras at the store, you should know what size to look for for both measurements.
If ordering online, try to find a site that has a return policy.

Use caution when letting a professional at the store choose your bra size. It’s a good idea to have an experienced professional measure your bust for you if you’re not sure about bra sizes – they can suggest styles that work for you. However, to choose the right bra you need to pay attention to:

Avoid stores with limited sizes. The staff at the store may intentionally sell you a shirt that doesn’t really fit, but they are in stock. Before you decide on a size, make sure the store also has smaller bust sizes (like 28 and 30) and larger cup sizes (DDD and larger). In the US you can go to reputable stores like Nordstrom and Dillard’s supermarkets.
Requires bra selection in both measurements. That way you’ll know what size you should try on if one measurement leads to the wrong choice.
Do not wear a bra when measuring. If an employee at the store tries to measure your breasts while you are still wearing your bra, the results may not be accurate. If you’re shy, wear a slim-fit tank top when you go to the store, and remove your bra when measuring.

Modern measuring style

Measure bust size. This is the easiest part of the measurement process – bust size is relatively stable and easy to measure.

Pull the tape measure around your body just below your breasts and take the measurement in centimeters. Make sure the tape measure is level and relatively snug. Both arms stretched out at the side. Rewrite the measurement.
For bras that are measured in inches, if the measurement is odd, you should try bras that are one size smaller and one level larger. ^{[1] X Research Source} For example, if you measure 31 inches, your bust might be 30 or 32.
If the measurement is an even number, then a bra with that bust size will most likely fit you, but you may need a smaller or larger bra depending on your body shape.

Determine the cup. Remember that the cup is not an absolute measure that stays the same – it changes proportions with the bust.

Bend down so that your chest is parallel to the ground. The purpose of this pose is to measure the entire breast – not just the protrusion when you are standing upright.
Measure around the upper body and place the ruler on the fullest part of the bust. Do not tighten the ruler too tightly – just tighten enough so that the ruler cannot move, but not so tight that it presses on the breasts. Rewrite the measurement.
Make sure to place the tape measure parallel to the ground. Do not place the ruler a few centimeters below your back, or you will get an uneven measurement. To avoid this error, you should stand in front of a mirror when measuring, or ask your husband/boyfriend or close friend to measure for you.
Calculate chest cup. To calculate your bust, subtract your bust measurement from the number you just measured. The difference between these two measurements will help you determine the cup:
- Under 2.5 cm = AA
- 2.5 cm = A
- 5 cm = BIG
- 7.5 cm = SIZE
- 10 cm = EASY
- 12.5 cm = DD
- 15 cm = DDD (E in British scale)
- 18 cm = DDDD/F (F in British scale)
- 20.5 cm = G/H (FF in British scale)
- 23 cm = I/J (G in British scale)
- 25.5 cm = J (GG in British scale)
- Most leading brands use the British cup scale: AA, A, B, C, D, DD, E, F, FF, G, GG, H, HH, J, JJ, K, KK , L, LL. If you go shopping in the US, you can see cups like DDD or DDDD. They are equivalent to E and F cups. If you are unsure, especially with larger cups, you can refer to the international bra size chart. ^{[2] X Research Source}

Try on to check

Try on the bust and cup bra you found in the steps above. You shouldn’t consider this your correct size until you’ve tried a few on, even then you often find yourself choosing different sizes for different brands or bra styles.

Wear the right bra. The “scoop and swoop” method is a way of wearing a bra to ensure that the entire breast fits in the cup:

After removing the bra from the hook, you need to stretch the shoulder straps. Wrap your arms over the strap and lean forward slightly so that your breasts are in the cup.
Fasten the bra with the large hook at the back. Don’t worry if you find it difficult to fasten, if you are trying on a shirt with a smaller bust you will have to stretch it to be able to fasten the hook on the back.
Still in a forward leaning position, grasp the underwire under the chest and pull back and forth to make sure the breasts are comfortably in the cup.
Slide your hand into one side of the cup and pull your breasts in the center, doing the same for the other side.
Maybe you have to adjust the length of the shoulder strap. Slide the straps off the shoulders and adjust the slide buckles so that they are short enough to hold the shirt in place but not to the body.

Check your bust size. The correct bust size will be the smallest size you will still feel comfortable wearing. (May be smaller than your actual bust measurement – bras are quite elastic, especially from size 42+). ^{[3] X Source Research} The hem should be tight enough that the bra can still support without putting too much pressure on the shoulder straps.

You can slide your finger along the inside of the hem, but not much more than that. As a general rule, you can only thread one fist under the back of your bra, just above your spine.
The shirt will fit on the largest button but may be too tight if you try to fasten it on the smallest button. The bra is designed this way so you can tighten the leg loops when the fabric starts to creep.
If your bra’s leg circumference is wide enough for you to wear comfortably at the smallest setting, try a smaller bra, for example if the 32D is too loose you should try the 30DD. Remember that you must change the cup when choosing a different bust – when decreasing each bust level, you must increase the cup by one level so that the two cups remain the same size and vice versa.
If you find that your bust is tight enough to cause pain, you should increase the cup one level because a bust that is too large or medium does not seem to fit when the cups are too small. If increasing the cup by one or more levels and the situation remains the same, you should increase the bust by one level and reduce the cup by one level, for example 28G to 30FF. However, you should try the first method before the second.

Traditional measuring style

Measure bust size. Wrap the tape measure around your rib cage, just below the bottom of your chest. Afterward:

If the measured value is even: Add 10 centimeters.
If the measured value is odd: Add 12.5 centimeters.
You should know that most brands no longer use this bust size system. The “plus ten” method was used by Warners in the 1930s when bra design was still in its infancy, and it doesn’t work well with modern bras. ^{[4] X Research Source} But you should be aware of the existence of this dimension system.

Measure chest cup. Stand up straight and wrap the tape measure around the fullest part of your chest. (Keep the ruler as horizontal as possible – make sure it doesn’t sag around the back.) Subtract this new measurement from the bust to get the cup:

Under 2.5 cm = AA
2.5 cm = A
5 cm = BIG
7.5 cm = SIZE
10 cm = EASY
12.5 cm = DD
15 cm = DDD (E in British scale)
18 cm = DDD/F (F in British scale)
20.5 cm = G/H (FF in British scale)
23 cm = I/J (G in British scale)
25.5 cm = J (GG in British scale)

Advice

Don’t be tempted to buy cheap bras that are the wrong size or of poor quality. For bras, you get what you pay for. Better to buy one bra that really fits than three uncomfortable ones!
If you want your bra to last and not stretch, never wear the same bra two days in a row, even after you’ve washed it. You should have a minimum of three to wash and cycle through, allowing the fabric to fully recover before being pressurized again.
Don’t think you have to buy the same size for every bra, or that you can buy any bra in your “true size” without trying it on. Different bra styles will fit different bust shapes, so two people using the same bra size may have to choose a different size for another bra.
Fit bra with leg loop supports 90% bust support, the rest 10% is borne by shoulder straps.
If you have uneven side cups, choose a bra with the larger side cup. You can help lift the small side of your chest by shortening the shoulder strap on that side a bit. If the size of the breasts is much different, you can wear silicone bra pads on the smaller breast.
Don’t care about anyone trying to determine a certain bra size based on your measurements alone – especially when they ask you to add extra centimeters to your bust measurement. As with skirt sizes, bra measurements have changed over the years, and the old measurement method no longer works for modern bras.
This is just a rough idea of what bra size to try on – the actual fit is more important than the measurements. Since most women have different body shapes, it’s quite common for two people to have the same measurements but have to choose very different sizes of bras.
People with D+ cups should wear bras with cups made of many pieces. The addition of side panels will help narrow the chest, creating a slimmer upper body.
Many bra companies pretend not to know that many women have cups under 28. However, in reality many people wear bras sizes 20, 22, 24 and 26. Some even wear smaller sizes. Remember that the bra material will stretch. Unfortunately, because bra companies pretend to be unaware of the existence of such bra sizes (which is more beneficial to them) it is almost impossible to find such bra sizes. You can repair your bra, but this is not entirely possible because you cannot fix the underwire and the risk of it being stabbed in the body after repair. If you need to fix your bra, you should buy a bra with a bust one level bigger and a cup two levels down. Since the bust and cup are proportional to each other, the frame in the larger cup cup will be larger. That’s why you should choose a shirt with a smaller cup so that the frame in it is shorter. Cups larger than D tend to vary quite a bit between brands, so it’s a good idea to ask the seller or check out customer reviews before buying online.

Things you need

Soft tape measure
Bras to try on

Steps