Bra size chart UK | How to use a bra size chart?

How does it really work a UK bra size chart? It seems simple and it is in a way. But you could be in between two sizes. Take these 4 steps to find your best bra size.

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Step 1. Taking your measurements

woman measuring bra size

A bra size is based on two measurements.

  1. measurement of the underbust and
  2. the measurement of the bust

Measure your band size. Hold the measuring tape a bit firm. Write down the inches or centimeters.


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measure tape bra size uk

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Measure your bust size. Hold the tape loosely over the fullest part of your breasts. Write down the inches or centimeters.


Step 2. Look up your number and letter in a bra size chart

I’ve added a bra size chart to give you an example.

For example:

  • your underbust is 71 centimeters
  • your bust is 84 centimeters

Your bra size would be 70B


Step 3. What if I may fit two bra sizes?

Another example:

  • your underbust is 77 centimeters
  • your bust is 83 centimeters

Your bra size would be 75AA



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But it might not be your best bra size!

Let me explain.

  • your band measurement is 77 centimeters, this is close to band size 80
  • your bust measurement is close to cup size AAA

This takes me to step 4!


Step 4. Play around a bit with your measurements

woman is measuring her bra size

We all have bra sister sizes. These bras differ in their number and letter but do have the same cup volume.

So maybe you wanna go up a band and go from 75 to 80.

What happens if you go from 75AA to 80AA because you only want the band to be a bit wider?

In order to keep the same cup volume, you would have to go down a cup size. This would be 80AAA.

Another example of sister sizes: bras 95D, 100C, and 90DD all have the same cup volume.

  • take some time to do your measurements
  • measure a couple of times in a row and compare your outcomes


Other articles you might like

Guide how to measure your bra size
How often does a bra size change?
Why wash your bras regularly?
Bra sister sizes do I have one?
All about teen bra sizing
Determine your best bra band size
Small bra size chart AAA-B
How to do the measurements at home
About the average UK bra size
Why is my bra hurting me?


Check your size in my bra calculator
of visit M&S for advise and size chart

measure tape bra size uk

Marks & Spencer | Find your Perfect Fit
UK | US | CA | IE | ES | FR | AU
select your shop/country

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