Did you know that most women wear the wrong bra size without realizing it? In addition, many are unaware of the different types of bras which are made to fit your body perfectly no matter what you wear. While the band on your bra may be comfortable to you, the cup size may be too small or too big. Our Bra Size Calculator will help you find your most comfortable, flattering fit right at home.
HerRoom Bra Size Calculator
You will need:
A non-padded bra
Calculate Your Bra Size In 3 Easy Steps
Measure for Band Size
A. Measure your underbust using a tape measure, making sure the tape is parallel with the ground. It should not be loose or binding. Exhale to get the smallest measurement possible.
B. Find your number (inches or centimeters) and enter it in the box below. Be sure to round all fractional measurements to the nearest whole number.
My band measurement is:
inches or centimeters
Step 2.Measure for Cup Size
A. While wearing a non-padded bra, stand straight with your arms at your sides and measure the fullest part of your bust. Make sure the measuring tape is parallel with the ground and not loose or binding.
B. Find your number (inches or centimeters) and enter it in the box below. Again, round all fractional measurements to the nearest whole number.
My cup measurement is:
inches or centimeters
Think this bra size is wrong? It could be - there is no 100% accurate measuring system. This size, however is your best starting point. Please see our “Sister Sizing Video” to learn what bra size change you may want to consider.
Women with cup sizes D and larger find manufacturers don't call the same cup size by the same letters.
HerRoom's exclusive Universal Cup Sizing™ solves this problem. Know your Universal Cup Size™
and find your correct bra size in any brand, every time.
Note: Although it’s quite easy to find a bra size with these two steps, any bra sizing system using a tape measure will not always give a totally accurate bra size. Several factors can influence your measurements, including:
the bra you’re wearing
the firmness of your breasts
the broadness of your back
the narrowness of your shoulders
We suggest watching our “Bra Sizing Video” for tips on accurate measuring.
Video: How to Fit a Bra
A video tutorial on how to measure for the proper bra fit.
Knowing your right bra size can be life changing.
The tape measuring system is just one of many ways to calculate your best fit.
This method isn't always completely accurate but it will give you a great starting
Keep in mind if your bust is larger this measuring system will give you the right
band size but not the right cup size.
Lets get started, first grab your measuring tape and put on your newest, best fitting
bra that has an underwire, is not padded or a minimizer bra.
If your breasts look like they are sagging, tighten the straps until your center
breast is halfway between your shoulder and elbow.
Finding your band size.
You can do this part yourself in front of a mirror or grab a friend to help.
Wrap the measuring tape directly under your bust, making sure its parallel to the
This is critical because if the tape measure isnt straight you will get an incorrect
Let out all the air from your lungs, making sure you get the smallest measurement
Our model measures 29 and a 1/4. If your band measurement isnt an exact number,
round to the nearest inch.
Using this number go to our band size chart and find your measurement and your estimated
If your measurement is 39 inches or more round to the nearest even number to find
your band size.
Adding inches to your band measurement came about just after World War II when the
ideal hour glass figure measured 36, 24, 36.
Women wanted to think their measurements were close to this ideal.
However a 36 inch bust measurement doesn't translate to a 36 inch underbust measurement.
So bra makers added several inches to make a womans bra size sound more desirable.
But with todays stretch fabric technology few more inches need to be added to your
underbust measurement in order to find your band size.
Finding your cup size.
Standing straight with your arms at your sides and breathing normally, wrap the
tape measure around your body at the fullest part of your bust.
The tape measure should just touch you and not feel binding.
Again the tape measure should be parallel to the floor.
Our model measures 35.
If your bust measurement isnt an exact number round to the nearest inch.
So now you have two measurements, our models band size is 32 and her bust measurement
We subtract our band size from our bust measurement to get a difference of 3.
A three on our chart translates to a C cup.
So according to the tape measuring system our models bra size is a 32C.
Now lets show you examples where the result is incorrect.
We know our next model is a 34D4. After exhaling, her underbust measurement is a
32 and a 1/2.
Referring to our chart, her band size is a 34.
There's an alternate measuring method to find your band size. measure above your
bust, under your arms and around your back.
This measurement doesn't need any additional numbers added but presents problems.
Where exactly should the tape measure land?
On our model this measurement is 35 and a 1/2 but you can see that the tape is not
parallel to the floor.
We get 38 and a 1/4 when we put the tape measure lower.
For these reasons we dont recommend this method to find your band size.
Moving to cup sizing our model is wearing a 34D4, so her measurement should be a
41 but its a 39, which is incorrect.
We measured our model again in a less supportive bra, this time she measured 37
and a 1/4.
As you can see, results can vary based on the type and fit of the bra you wear.
The tape measuring system isnt always perfect.
If your not happy with the results, check how your bra fits using some basic techniques
Scroll down to the bottom of the page and select bra fitting, from there click on
our perfect bra fit checklist.
Here you'll see a long list of bra fit problems, the reason for these and suggestions
to give you the correct size.
For women who are full busted or plus sized - wear a bra size 38D and up, sizing to find your best fit should start with identifying what needs to be improved from your current bra size: Is the band too tight? Are the cups the wrong size? Find solutions to most bra fitting problems here.
Browse HerRoom’s complete selection of Plus Size Bras here.
How to manually measure and fit a bra: (and how the Bra Calculator works)
Note: After a 38 band size, the band size should be the closest higher, even number to your actual measurement. For example, a 41.5" measurement is a 42" band.
STEP 1: Measure for band size:
Measure your underbust using a tape measure, making sure the tape is parallel with the ground. It should not be loose or binding. Exhale a deep breath to get the smallest measurement possible.
After a 38 band size, the band size should be the closest higher, even number to your actual measurement. For example, a 41" measurement is a 42 band.
Band Size Chart
If Your Measurement is:
Your Band Size is:
After a 38 band size, the band size should be the closest higher even number to
your actual measurement So, 41.5" is a 42 band. A 41" measurement is a 42 band.
STEP 2: Measure for cup size:
While wearing a non-padded bra, stand straight with your arms at your side. Measure at the fullest part of your bust, making sure the measuring tape is parallel with the ground and not binding. Be sure to round all fractional measurements to the nearest whole number.
Step 3. Calculate your bra size*
Subtract your band measurement (step 1) from your cup measurement (step 2). Generally, for each inch in difference, the cup goes up by one size. See the cup size conversion chart below.
Step 1: 34" under measurement = 36" band size
Step 2: 39" over measurement
Step 3: 39" - 36" = 3" or C Cup Size
Your Size is probably a 36C
Note: The cup size calculation starts falling apart at 4 inches larger than your band size. If you have pendulous breasts, your measurement will not be accurate.
Universal Cup Sizing®
* Cup sizes larger than a D are sometimes sizes as different letters by different brands. For example, a DDD cup size in one brand may be called an E or F in other brands. Finding your UCS® can help you find your correct fit in any brand at HerRoom. Learn how to find your UCS® bra size™
Thousands of bras to choose from can make it difficult to select the bra that fits your body, your style, and your outfit. Our list of The Pros & Cons of Bra Styles describes the various features of many bra styles.
Already Know Your Bra Size?
See what other women in the same size are buying. Enter your bra size below to find out! (ie: 32C, 36DD, etc.)
Welcome to HerRoom, the world’s premier online lingerie authority. Founded by Tomima Edmark in 1998, HerRoom has grown from bras and panties to include swimwear, sleepwear, and beyond. We offer over 250 brands, from classic brands you love like Wacoal, Chantelle, and Vanity Fair, to some you may not have heard of—Fantasie, Prima Donna, Elomi—but are sure to love. We work hard to provide you with as much information as possible, including extensive fit information, measured drawings of each bra, and honest customer reviews. Whether you’re a 28A or a 58J, we’re confident you’ll find something you love at HerRoom!