Sizes in underwear and why they do not follow clothing sizes
Short answer: Underwear is sized by the hips, not by the waist or chest. That is why your briefs size can differ from your trouser or dress size without either of them being wrong. They are simply based on different measurements.
The hips are the reference
Briefs and underwear sit over the hips and seat, which is why the hip measurement decides the size. Trousers, on the other hand, are often measured at the waist, and dresses and tops at the chest. Each garment is built around the part of the body where it sits and supports. Read more in our guide to briefs and underwear.
Why they can differ
If you have a narrow waist and wider hips, your briefs size will be larger than your trouser size. If you have a wider waist and narrower hips, it can be the other way round. This is completely normal and does not mean either size is wrong. Bodies have different proportions, and each size reflects its own measurement.
Stretch changes the picture
Underwear is almost always made from stretch fabric, because it needs to follow the body closely. This means one size covers a wider range than in firm clothing. If you are at the top of a range, briefs can feel tight at the edges, and the next size up is often better. See bamboo underwear for women.
The cut matters
A hipster, a brief and a high waisted style in the same size fit differently, because they sit at different points on the hips. A high waisted style reaches towards the waist and can feel tighter if your waist is wider than your hips. Always check the cut before choosing a size from the chart.
Bras have their own system
Bras are measured in two dimensions, band and cup, and have nothing to do with clothing sizes. The band is measured just under the bust, and the cup depends on the difference between that and the fullest part of the bust. A bra without underwire often has simpler sizing, but uses the same measurements. See bamboo bra without underwire.
Socks follow shoe sizes
Socks are sized in shoe size ranges, which is yet another system. A range like 41 to 45 covers several shoe sizes, and you choose the range your shoe size falls in. If you are on the border between two ranges, the larger is often better so the sock does not pinch over the instep. See all bamboo socks for men.
Measure instead of guessing
Measure around the widest part of your hips with the tape level all the way round, and use the chart for the model you are considering. Stand with your feet together and do not pull the tape tight. Then you have a number that fits that specific garment and do not need to guess from your trouser size.
When you are in between
If you are between two sizes in underwear, size up. Briefs that are too small dig in at the edges all day, while a pair that is slightly large still fits well, because the fabric adapts to the body. The exception is the bra band, where the firmer band is usually the right choice.
Watch the fit over time
Underwear is washed often, and the elastic changes a little over time. If briefs sit loose at the waistband after many washes, it is a sign of wear and not the wrong size. Wash according to the label and avoid high heat in the tumble dryer, so the elastic lasts longer.
Frequently asked questions
Why is my briefs size larger than my trouser size?
Because briefs are sized by the hips and trousers often by the waist. If you have a narrow waist and wider hips, your briefs size will be larger, which is normal.
Do bras follow the same system?
No. Bras are measured in band and cup and have their own system. The band is measured under the bust, and the cup depends on the difference to the bust measurement.
Where do you measure for briefs?
Around the widest part of the hips and seat, with the tape level all the way round. Stand with your feet together and do not pull the tape tight while measuring.
See our range of Boody underwear.
