This is how to measure your bra size

how to measure bra size
(Image credit: Gel Nat)

Did you know most women wear the wrong bra size? Well this wouldn't be the case if we all knew how to measure our bra size, would it? So we thought we'd grill two lingerie experts on everything you need to know about the subject, including how often to change bras, how often to wash them and everything else you need to know about the lingerie staple.

How to tell if you're wearing the wrong bra size

Check the cups

Figleaves Garment Technologist Victoria Shelton says, 'The cups should fully encase your breasts with no spilling out or sitting away.'

Check the underband

Debby Duckett, Buying Director at Boux Avenue, explains, 'if it is rising up your back, lifting up at the front, or is too tight that it’s causing discomfort, we’d recommend going for a bra fitting.'

Check the straps

Victoria says, 'The straps should sit comfortably on your shoulders with the majority of the support coming from the underband. The underband should be snug, supportive and sit level without riding up.'

Check where the bra sits

Debby says, 'It’s also worth checking where your bra is positioned. If it’s standing away at the centre front, or if the wire is sat on breast tissue, it’s not fitting you properly. You can check this by pressing the wire at the end; if the wire bounces it means it is sat on breast tissue and isn’t secure.'

How to measure your bra size

The easiest way to get your bra measurements is by going in for a bra fitting, however if you don't have time, or would rather do it at home, then Debby says you can do it in three easy steps.

  1. Grab a tape measure and start with measuring your underband, which is the part of the bra that provides the most support. Standing in front of a mirror with the centimetre side facing outwards and keeping the tape measure straight, level and tight, measure the circumference of your body, just underneath your bust.
  2. Use the conversion chart below to find your underband size.
  3. You can then work out your cup size from there, by comparing the new underband size to your previous underband size. If your underband size is now smaller, it’s likely that you’ll need to go up a cup size. If your underband size is the same but your bust is spilling out of the cups, you’ll need to go down a cup size. If the cups are gaping and there is space, go down a cup size.

Bra size measurement UK

Swipe to scroll horizontally
CMBack band

How often to go for bra fittings

Your breast size can fluctuate due to varying factors like hormones, ageing, weight gain etc, so experts recommend getting bra fittings every six months.

How to check your bra fits

Victoria says, 'I would recommend checking the fit every few times you wear the bra. Check the straps are sitting correctly on the shoulders and with the right amount of adjustment. The underband should be snug but supportive, over time the elastane in the bra will become worn and less supportive, it is vital to change your bra at this point.

How long do bras last?

'With regular wear, bras can last from 6 months to a year,' Victoria adds.

When is it time to change your bra?

'Colour and shape are the two main areas that tell you when it’s time to replace a bra. If the underband is too loose on the tightest hook or the straps are no longer staying in place, your bra is no longer giving you the support you need. If the colour has started to fade and the fabric has gone a little frayed, you have the perfect excuse to treat yourself to some new lingerie!' Debby says.

Penny Goldstone

Penny Goldstone is the Digital Fashion Editor at Marie Claire, covering everything from catwalk trends to royal fashion and the latest high street and Instagram must-haves.

Penny grew up in France and studied languages and law at the Sorbonne Nouvelle University in Paris before moving to the UK for her MA in multimedia journalism at Bournemouth University. She moved to the UK permanently and has never looked back (though she does go back regularly to stock up on cheese and wine).

Although she's always loved fashion - she used to create scrapbooks of her favourite trends and looks, including Sienna Miller and Kate Moss' boho phase - her first job was at, sourcing the best deals for everything from restaurants to designer sales.

However she quit after two years to follow her true passion, fashion journalism, and after many years of internships and freelance stints at magazines including Red, Cosmopolitan, Stylist and Good Housekeeping, landed her dream job as the Digital Fashion Editor at Marie Claire UK.

Her favourite part of the job is discovering new brands and meeting designers, and travelling the world to attend events and fashion shows. Seeing her first Chanel runway IRL at Paris Fashion Week was a true pinch-me moment.