Chest width on a flat laid top

Short answer: Measure two centimetres below the armhole from edge to edge. Double the figure to get the circumference, then compare it with your own chest measurement plus an allowance for movement, and you will know how the top will fit.

The measuring point should be the same every time

Two centimetres below the armhole is the point most guides use. Measure there every time and your figures compare directly. Do it on bamboo t-shirts for women and on everything else in your wardrobe. You get a set of numbers showing the width you prefer.

The circumference is double

The flat measurement is half the circumference, because the top lies double on the table. Work it out before comparing with the guide or your chest measurement. A top measuring fifty centimetres flat has a circumference of one hundred. Do the same when comparing bamboo slips or other items in a guide.

The allowance decides the fit

The difference between the item's measurement and your body is called the allowance. If the item is four centimetres larger than your body, the top sits close. At ten centimetres larger, it sits loose and relaxed. See the bamboo hoodie for women, where a looser fit often suits quiet days at home.

How to measure your own chest

Stand relaxed and place a soft tape level around your chest at its widest. Do not pull tight, just let it rest lightly. Measure over the bra or underwear you normally wear beneath the top. Write the figure down and add the allowance you want before comparing with the guide.

Elastane changes the maths

If the top contains elastane or other stretch, the item can measure smaller than your body without feeling tight. The fabric gives and follows the body. This applies especially to close fitting tops and underwear. Always read what the fabric is made of, so you do not size up out of worry.

Smooth the fabric out fully

Folds and ripples give a wrong measurement, often by several centimetres. Lay the top on a table and smooth it from the centre to the sides. Do not pull the fabric, let it lie naturally. Then measure straight across from one side seam to the other, parallel to the hem.

Compare with a top you like

The best reference is a top that already fits the way you want. Measure its width, double it and compare with the guide for the new item. If the figures are close, you get a similar fit. If they differ a lot, you know in advance whether the new top will sit closer or looser.

Think about how you will wear it

What you use the top for should guide how much allowance you choose. A top under a cardigan should sit close so it does not add bulk. A top for relaxing at home can have more room. Wash as the label says, so the fit stays as it was when you first measured it.

Frequently asked questions

How much allowance is right

Four to six centimetres for close fitting, ten or more for loose. Choose based on how you want the top to sit.

Do you measure above or below the armhole

Below, two centimetres down. Most guides use that point, so your figures compare directly.

What if the top contains elastane

Then the item can measure smaller than your body without feeling tight, because the fabric gives and follows you.