Bra Size Calculator

Welcome to the HerRoom Bra Size Calculator. But, we need to tell you up front, that any bra sizing system where a tape measure is involved will not be totally accurate. The reason? A lot of factors can affect your measurements – the bra you’re wearing, the firmness of your breasts, the broadness of your back, the narrowness of your shoulders… These factors and more can give you a false bra size once you’ve measured yourself. And, for women who wear a bra size 38D and larger, using this measuring system as a bra size calculator is frankly a mistake. Instead you should be bra sizing starting with your base bra size and tweaking this size based on what you don’t like about your current bra size (check out our Poor-fitting Bra Examples)

So, here’s the bra size calculation using a measuring tape. But, be aware that it is not always accurate. And, HerRoom encourages you to watch our “Bra Sizing Video” for tips on accurate measuring.

HerRoom Exclusive: Bra Fitting Video

Already know your size? See what other women in the same size buying. Enter your bra size below to find out!

(ie: 32C, 36DD, etc.)

How to measure and fit a bra in three easy steps

STEP 1: Measure for band size:

Keeping the measuring tape parallel with the ground, measure around your bra directly under your bust after expelling all air from your lungs - you want this measurement to be as small as possible. Round all fractional measurements to the nearest whole number.

Measure using the instructions above, then find your band size here

If Your Measurement is:

Your Band Size is:

After a 38 band size, the band size should be the closet 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:

Standing straight, with your arms at your side, measure at the fullest part of your bust (while wearing a non-padded bra) making sure the measuring tape is parallel with the ground and not binding.
Round all fractional measurements to the nearest whole number.

Need help?
Expanded bra cup measuring instructions »

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 here.

Example:
Step 1: 34" under measurement = 38" band
Step 2: 40" over measurement
Step 3: 40" - 38" = 2" or Cup "B"
Your size would be 38B

The cup size calculation starts falling apart at 4 inches larger than your band size, and if you have droopy or pendulous breasts, your measurement will not be accurate.

If The Differtence Is:	Your Standard Cup Size Is:
0" to 1/2" (1.3cm)	AA
1/2"- 1" (2.6 cm)	A
2" (5.1 cm)	B
3" (7.6 cm)	C
3" (7.6 cm)	C
4" (10.2 cm)	D
5" (12.7 cm)	DD * or E *
5" (12.7 cm)	DD * or E *
5" (12.7 cm)	DD * or E *
6" (15.2 cm)	DDD * or F *
7" (17.8 cm)	G *
8" (20.3 cm)	H *
9" (22.9 cm)	I *
10" (25.4 cm)	J *

*Please Note: This bra measuring method becomes very unreliable at bra sizes 38D and larger.

Next Section: Bra Fit Tips & Tests »