My articles contain affiliate links. Please see my full disclosure at the bottom of the page.



I believe in a well-fitted bra for every woman!

A bra in the wrong size doesn’t make you feel good. No, not at all. My calculator helps you find your best bra size!

Feeling and touching your bra all day long doesn’t give you confidence.

This is uncomfortable and irritating for sure.


What does my calculator do?

woman looking down wondering if her bra size might have changed

Our body sizes may change during life, and so may our bra size.


It is my mission to invite as many women (and girls) as possible to find their best bra size.

  • please play a bit with the measurements
  • you’ll see how close bra sizes can be!
  • it may well be that you might fit two different bra sizes
  • different brands may have a different fit
  • find out your true bra size or sizes

Calculator small cups
(AAA – C cups)

Calculator larger cups
(D cup and up)


How come we end up wearing the wrong-sized bra?

We keep reading about the high percentages of women who wear the wrong bra size (varying from 60 to 80%).

I always thought these percentages to be a bit high. But after measuring myself and other women I found out that many women indeed still wear the wrong bra (including me).


Marks and Spencer | Women's Fashion 2024

At Marks and Spencer, you'll find advice and tips on styles to suit you | M&S BraFit Guide


Of the first four women I measured, three of them were not wearing the right bra.

They knew it, they felt it, and saw their bad-fitted bra in the mirror. These women all had different body and bra sizes, from AA to D+ cups.


Reasons why we stick too long with the wrong bra

woman holding several bras with a wrong size

Wearing a wrong-sized bra will surely NOT make you happy 😐


Why do we hold on to a bad-fitted bra?

  • we wear this bra size for many years now, never really wondering if the size is still the right one
  • we never had a proper bra size in our lives before, and still accepting this
  • our bodies and breasts have changed (weight changes, childbirth, operation, etc.), but we haven’t checked our bra sizes
  • we know the bra isn’t right but we don’t take the time to measure ourselves or get a bra fitting
  • someone else measured our bra size and we keep it, although we don’t feel happy with the bra


Measuring yourself

measuring your bra size and use our bra size calculator

Measuring yourself is not difficult, it may take no more than 10 or 15 minutes.


First, you measure your underbust and bust size. So that’s two measurements.

Secondly, you’ll compare your measurements in a bra size chart or in a bra size calculator.

Voila, that’s it.


Measuring tips

  • My advice is to measure a couple of times and write down the outcomes. Only a slight difference in your measurements could mean you would fit another bra size.
  • Don’t let this scare you! It’s important for you to find out if you’re just in between two bra sizes. It could mean you would fit two different bra sizes and they both fit you just fine.
  • For example. Your bra size is 40D. Your band size is however close to 38 as well. You might fit 40D, but you might also try 38DD/E.
  • When you go up or down a band size, your cup size volume will change too. If you want to keep the same cup size, but need another band size? Just go down or up a cup size as well to keep the same cup volume.


My bra guides

Full guide on bra sizing
Bras for AAA-C cups & calculator
Bras for D+ cups & calculator
Comfy Loungewear Guide
All my blogs


What's your bra size? See my calculator

Marks and Spencer Lingerie

Find the right bra at your M&S Store
M&S UK | M&S US | M&S CA | M&S AU