bra size calculator - measurements
Frame measurement
Bust measurement
In United States
Bra size
Cup size
In continental Europe
Bra size
Cup size
In United Kingdom
Bra size
Cup size

Bra Size Calculator

By Bogna Szyk and Aleksandra Zając, MD
Last updated: Dec 27, 2020

This bra size calculator can help you in finding and converting your bra size to most common international sizes - continental Europe, USA and UK. If you ever wondered how to calculate your bra size according to European charts and what is the correct bra size for you (or your girlfriend 😀), keep reading to find out!

Taking measurements for correct bra size

You need to take two measurements. Take them while braless or while wearing a non-padded bra to ensure maximum accuracy of results.

  • Bust measurement: measure at the fullest point of your bust with a soft measuring tape. Make sure that the tape is not too tight by breathing in and out. Note the measurement down (if you decide to round it, remember to round the number up).
  • Frame measurement: measure around the bottom of the band, directly under your bust. Check whether the measuring tape is level and not too tight. Again, don't round the measurement or round it up to the nearest full number.

Looking for a bikini bra size? Try also our bikini calculator to check the bikini fashion that will flatter your body the most.

How to calculate bra size?

  1. First, take your measurements according to the rules listed above.
  2. Subtract your frame measurement from the bust measurement. This difference will determine your cup size.
  3. Compare your results with bra size charts. You can also use our bra calculator instead :)

In the table below you can see, how the bust-frame difference determines the cup size.

CSV To HTML using
Difference (inches [cm]) Cup size in the U.S. Cup size in Australia Cup size in the UK
1 (2.5) A A A
2 (5.1) B B B
3 (7.6) C C C
4 (10.2) D D D
5 (12.7) DD/E DD DD
6 (15.2) DDD/F E E
7 (17.8) DDDD/G F F
8 (20.3) H G FF
9 (22.9) I H G
10 (25.4) J I GG
11 (27.9) K J H
12 (30.5) L K HH
13 (33) M L J
14 (35.6) N M JJ
15 (38.1) O N K
16 (40.6) P O KK
17 (43.2) Q P L
18 (45.7) R LL

Making sure your bra fits

Even if you have used our correct bra size calculator to find the proper size, it does not guarantee that every bra will fit. Use these tips to make sure you never buy a bad bra again!

  • Begin with putting your bra on properly. Bend forward at the waist, then put on the bra and hook it.
  • Adjust the band to make sure that the back of the bra is leveled with the front.
  • You should be able to slide only one finger underneath the band. If it is more loose, you should try on a smaller size.
  • After you tighten the band, shorten the straps.
  • Put on a close-fitting shirt over the bra to examine how it looks beneath clothing for a final check.
  • Choose a bra that fits perfectly when you secure the last hook. Your bra will loosen in time, so you will be able to make it fit you again by using the inner hooks later.

Make sure to check out our ideal weight calculator, too!

Wrong bra signs

Taking measurements is only the beginning, but nothing works better than your own experience. So, before buying a bra, we highly recommend you to try it on. The cups may be a different shape to what your used to, the styles may make the bra sizes uneven - even among the same bra brand! Check out this list - if you experience one or more of these signs, you're probably wearing the wrong size bra, or it is wrongly adjusted.

  • Red marks on the skin - either from straps or underwires. The first case means that either the straps are pulled too tight or the band of the bra doesn't support your bust enough. If an underwire pokes your skin, the cup is way too small.
  • Breasts spill from the bra - the cup is too small.
  • The cup sticks out - either the cup is too big, or this is not your bra type.
  • The band moves up on your back - the band is too loose. To offer support, the band needs to sit in one fixed position just under your bust.
  • The band feels tight - it's either the band is too tight, or the cup is too small. Try a cup up first.
  • You suffer from the back pain or the neck pain - red flag! Your bra is not supporting your breasts at all. Try to adjust it as much as you can, but there is a 99% chance you'll need to buy a new one. Try our calculator first, or get a professional bra fitting in order to be as satisfied as possible with your purchase!

Bras for special tasks

Know your size already? Perfect! Now take a look at the most popular bra types and what can they offer to you.

I want to...

rock my attire tonight push-upadds a smooth line and even a size to your bust
cage gives you an intriguing cleavage
stick-on the one and only for those backless evening dresses. make sure to choose a good brand so you can rely on the glue!
get comfy non-padded brasnon-padded bras have an advantage over padded ones: they're simply softer
wireless less is more - the less stiff the bra elements, the more comfortable you are
get some special support sports brabeing comfortable while exercising requires sound breast support
maternity bra allows you to breastfeed your baby without taking all your clothes off

After capturing the perfect bra, there's time for perfect, made-to-measure clothes as well. Try our circle and pleated skirt calculators if you're in to sewing your own clothing. You can also take a look at the rest of our clothing calculators.

Bogna Szyk and Aleksandra Zając, MD