The 34B bra size used to be the most common one, but as the average bra size in the US keeps increasing that’s no longer the case. 34B boobs can be considered medium sized.
In this article, we’ll look at how to measure if you’re a 34B bra size, how big this size is, what 34B breasts actually look like, what are the sister sizes of this bra size, and everything else you may want to know about it.
Let’s dive in!
What Is a 34B Bra Size?
A 34B bra size is the bra size where the band measurement (measured right under the breasts) equals 34 inches and the bust measurement (measured at the center of the breasts where they’re the largest) equals 36 inches.
This might sound confusing, so let’s clear it up.
Bra sizes are usually defined by a number and a letter (34B, 32B, 36D, and so on). The number and the letter stand for different measurements, so it’s important to get both right.
The first thing to measure is the “number” part, which stands for your band size. To find this number, wrap a measuring tape just below your breasts and measure all the way around your ribcage. Do this while naked and standing straight to get the most accurate measurement.
The number of inches you get this way is your band measurement (the “number” part of the bra size).
If you get an odd number, increase it by 1 to get to an even number, since that’s how bra sizes are usually defined (for example, if your band size is 31, round it up to 32).
In a 34B bra size, the band size measured like this will equal 34 inches (or 33 inches).
Some online resources will tell you to add 4 inches to your band size. This is an outdated method that most bra manufacturers don’t use anymore. So, it’s probably best to ignore such advice if you find it online.
Once you have your band size, you need to measure your bust size as well. Take a measuring tape once again, but this time wrap it across your breasts, where they’re the largest.
In a 34B bra size, the bust size measured as explained here will be equal to 36 inches.
Finally, calculate the difference between your bust size and your band size.
If the difference is 1 inch, you’re an A cup, if it’s 2 inches, you’re a B cup, and so on following this table.
In a 34B bra size, the difference between the bust size and the band size is 2 inches (36 inches – 34 inches = 2 inches). That’s where the “B” in “34B” comes from. The “34” in “34B” comes from the band measurement.
More About the 34B Bra Size
The 34B bra size is actually a very common, if not the most common bra size. It’s a fairly average size, with 34B boobs generally not being considered neither small or large.
Since it’s so common, there’s a wide selection of 34B bras, in all styles and colors. In general, the B cup size is along the C cup size regarded as one of the most desirable cup sizes.
What 34B Boobs Look Like (34B Bra Size Examples)
We discussed a lot about the 34B bra size, but you’re probably wondering what 34B boobs actually look like. Here, we’ll give examples of some celebrities that are thought to wear a 34B bra.
When it comes to celebrities, the B cup size in general is probably the most common one. So, it’s no surprise that there are some very prominent examples of the 34C bra size as well.
A very famous example of the 34B bra size is singer Rihanna. This puts her band size at around 34 inches, and her bust size at around 36 inches.
34B Sister Sizes (34B Bra Size Equivalent)
Closest sister sizes of the 34B are the 32C and the 36A. The 32C is one cup size larger and one band size smaller, while the 36A is one cup size smaller and one band size larger. Other sister sizes of the 34B are the 28DD and the 30D.
If you’re not familiar, sister bra sizes are different sizes that have the same cup volume. For example, the 30D, 32C, 34B, and 36A will all give you roughly the same fit. Since the band size of sister bra sizes increases as the cup size decreases, they can hold a similar amount of breast tissue.
Sister bra sizes can be useful if you can’t find a bra in your exact bra size. In such a case, a sister bra size is an option. Another use case of sister bra sizes is if your exact bra size isn’t comfortable enough even though the cups fit well.
For example, the underband might be too tight or too loose. If the cups fit well but the underband is tight, you can try a sister size up (one band size larger and one cup size smaller. For example, if the band of a 34B bra is tight, try a 36A.
On the other hand, if the underband is loose, you can try a sister size down (one band size smaller and one cup size larger). For example, if the band of a 34B bra is loose, try a 32C.
34B Bra Size in Inches
Measured in inches, a 34B bra size means that your band measurement equals 34 inches (that’s where the “34” in “34B” comes from) and your bust measurement equals 36 inches. The difference between the bust size and the band size is 2 inches, which translates to a B cup size (that’s where the “B” in “34B” comes from).
34B Bra Size in Cm (34B Bra Size in Europe)
Measured in centimeters, a 34B bra size means that your band measurement equals 86 cm (equal to 34 inches, which is where the “34” in “34B” comes from) and your bust measurement equals 91 cm. The difference between the bust size and the band size is 5 cm, which translates to a B cup size (that’s where the “B” in “34B” comes from).
34B vs 34C
A 34B bra size and a 34C bra size both have the same band measurement of 34 inches (which is where the “34” in 34B and 34C comes from). But, a 34B bra size has a bust measurement of 36 inches, while a 34C bra size has a bust measurement of 37 inches.
Given this, a 34C bra size is one cup size larger than a 34B bra size. In other words, 34C boobs are one inch larger than 34B boobs.
32C vs 34B
A 32C bra and a 34B bra are sister sizes. More specifically, the 32C bra is one sister size down from a 34B. This is because a 32C bra is one band size smaller, but one cup size larger from a 34B bra size.
32B vs 34B
A 34B bra size and a 32B bra size both have a 2-inch difference between the bust size and the band size. But, a 34B bra size has a band measurement that’s roughly 2 inches larger compared to the 32B (34 inches compared to 32 inches). Also, a 34B bra size has a bust measurement that’s 2 inches larger compared to the 32B bra size (36 inches compared to 34 inches).
Difference Between 34A and 34B Bra Sizes
A 34B bra size and a 34A bra size both have the same band measurement of 34 inches (which is where the “34” in 34B and 34A comes from). But, a 34B bra size has a bust measurement of 36 inches, while a 34A bra size has a bust measurement of 35 inches.
Given this, a 34A bra size is one cup size smaller than a 34B bra size. In other words, 34A boobs are one inch smaller than 34B boobs.
34B vs 36B
A 34B bra size and a 36B bra size both have a 2-inch difference between the bust size and the band size. But, a 36B bra size has a band measurement that’s roughly 2 inches larger compared to the 34B (36 inches compared to 34 inches). Also, a 36B bra size has a bust measurement that’s 2 inches larger compared to the 36B bra size (38 inches compared to 36 inches).
36A vs 34B
A 36A bra and a 34B bra are sister sizes. More specifically, the 36A bra is one sister size up from a 34B. This is because a 36A bra is one band size up, but one cup size down from a 34B bra size.
34B vs 36C
A 36C bra size is bigger than a 34B bra size, both in terms of band measurement and in terms cup size. A 36C bra size has a band size that’s roughly 2 inches larger than the 34B (36 inches compared to 34 inches), and a bust size that’s roughly 3 inches larger than the 34B (39 inches compared to 36 inches).
Also, the 36C bra size has a 3-inch difference between the bust size and the band size, while a 34B bra size has a 2-inch difference between the bust size and the band size.
34B Bra Size Infographic
FAQ
What Bust Size Is a 34B?
A woman wearing 34B will have a bust size of 36 inches (91 cm). Her band size will be 33-34 inches, which means that the difference between the bust size and the band size will equal roughly 2 inches (that’s why the cup size equals B).
What Is the Next Bra Size From 34B?
If you go one band size larger, the next bra size from 34B is 36B. If you go one band size smaller, the next bra size is 32B. On the other hand, if you’re referring to cup sizes, the next bra size from 34B is 34C (one cup size larger) or 34A (one cup size smaller).
How Many Inches Is a 34B Bra Size?
A 34B bra size is 34 inches in band measurement and 36 inches in bust measurement. The difference between the bust size and the band size equals 2 inches, which is where the B cup size comes from.
Is 34B Small or Medium?
The 34B bra size can be considered a medium bra size, although it depends. For example, in countries such as the US, a 34B bra size is below average. On the other hand, in many Asian countries, a 34B bra size is well above average.
Is 32C the Same As 34B?
No, 32C is not the same as 34B. A 32C bra has a band measurement of 32 inches (this measurement is 34 inches for a 34B) and a bust size of 35 inches (this size is 36 inches for a 34B). However, the 32C and the 34B are sister sizes, meaning that they’ll hold roughly the same amount of breast tissue.
Is 32B or 34B Bigger?
A 34B is a bigger bra size than a 32B. This is because a 34B bra size has a band measurement of 34 inches (while a 32B has 32 inches) and a bust measurement of 36 inches (while a 32B has 34 inches).
Conclusion
In this article, you learned all you need to know about one of the more common, medium-sized bra sizes out there, the 34B bra size. Among other things, you learned how big 34B breasts actually are, how to measure if you should be wearing a 34B bra, what are the sister sizes of this bra, and what 34B boobs actually look like.
The founder, editor, and writer of most articles on Ultimate Bra Guide. An experienced bra fitting specialist turned blogger. My website Ultimate Bra Guide has been featured in relevant publications such as Glamour, Bustle, Elite Daily, Alldaychic, Everyday Feminism, and so on. Get to know me better at our about page.