Bust and underbust measurements, how to use both numbers

Short answer: Your bust and underbust measurements tell you two different things about your body, and they work best together. Measure both without pulling tight, compare them with the size chart, and choose the size that suits both numbers.

What the two numbers tell you

The underbust is the circumference just under the chest and decides how wide and snug the fabric should sit around your body. The bust is the circumference at the fullest point and decides how much room you need at the front. Each number answers its own question, so one alone rarely gives the right size in a chart.

How to measure the underbust

Stand up straight with your arms down and your shoulders relaxed. Place a soft tape measure around your body just under the chest, level all the way round, so it does not creep up your back. Pull it snug without squeezing, and read the number once you have breathed out.

How to measure the bust

Place the tape around the fullest part of the chest and across the shoulder blades, again level all the way round. Tape and body should touch without pressing into the skin. If you are unsure, measure twice, because a tape that hangs crooked can shift the number enough to make you pick the wrong size.

Why both numbers count

If you only look at the bust, you may end up with a size that is too loose across the back or too tight under the chest. The gap between the two numbers describes your shape, and that shape decides how clothes sit on the body. Always check both numbers in the chart before you choose a size.

When the numbers fall between two sizes

This happens to many people and is not a mistake in your measurements. Think about what you would rather avoid, pressure under the chest or too much air in the fabric. Soft, stretchy fabric gives a little and can handle the smaller size, while firmer fabric is often more comfortable in the larger one. Read the size notes on the item too.

Measuring for knickers and tops

Knickers follow the hips and waist, while tops follow the bust, but the thinking is the same, measure first and choose from the chart afterwards. You can browse the range of bamboo knickers, and for the upper body have a look at bamboo tops for women, where the bust is the most important number.

When to measure again

Your body changes a little through the month and over the years, so measure again when clothes no longer fit as they did. Measure in thin underwear or none, not over a thick jumper, or the number will come out too big. Save your measurements in your phone so they are at hand next time you shop.

Try on, move and wash

Once you have chosen, try the piece on and move, raise your arms, sit down and lean forward. If it feels good while you move, the size is right. Wash new clothes as the care label says, and expect the fabric to settle a little. You can find more styles among bamboo underwear for women.

Frequently asked questions

Should I measure with or without underwear on?

Ideally in thin, close fitting underwear or none, so the number shows your real shape. Thick clothing on top adds centimetres and makes you pick a size that is too big.

What if my measurements do not fit the chart?

First pick the size that suits the underbust, then check whether the bust falls within it. If none fits exactly, choose by what matters most to you, and remember that stretchy fabric gives a little.

How often should I measure again?

Measure again once a year or whenever the fit changes. Bodies change over time, and a quick measurement takes a few minutes and saves you from buying a size that does not fit.

You can find the full range at Copenhagen Bamboo.