While it’s quite easy to buy the right size knickers, the same isn’t true of bras. An ill-fitting bra isn’t only uncomfortable; it can lead to back problems. Despite this, few women know how to take their bra measurements properly – which is why so many end up with uncomfortable underwear and backache.

Few stores offer a professional bra fitting service these days and many people prefer to measure themselves. Even fewer sell bras that actually conform to the measurements stated on the labels. A poorly made bra is as disastrous as a poorly fitted one, which is why it’s essential you buy your underwear from a good lingerie specialist. Once you’ve found one, it’s essential you have a professional bra fitting, before you ever start thinking about the style or colour.

Your breast size may fluctuate with hormone levels, so avoid being measured just before a period. (Some women buy two bras, one a cup size bigger, so they’re comfortable throughout the month). When you’re measured, the assistant will take two measurements or you can easily do this yourself. The first is the under bust measurement, taken just below your bust, around your ribcage. This tells the assistant your bust size in inches. The second, over bust measurement is taken round your chest at the fullest point. The difference in inches is read off on a chart to give the cup size.

It can be a good idea to take two or three measurements over the course of a month before buying your lingerie. This will give you a true average. After that, you can buy a bra that will safely match your knickers.