Half chest (pit to pit)

Half chest, or pit to pit, is the width of a garment laid flat, straight across from one armpit seam to the other. It is half the garment's chest circumference: double it before comparing with a chart in circumferences. It is a garment measurement, so it already includes the room the garment leaves over the body.

How to measure

1. Lay the garment flat, front up, buttoned or zipped, smoothed out without stretching.
2. Find the two points where the sleeves meet the body, under the arms.
3. Measure straight across from one to the other.
4. Double it for the circumference: 53 cm laid flat is 106 cm around.

On a size chart

The Men's T-shirts and tops template has it in its garment tab, captioned "Garment measurements, laid flat":

The body tab of the same template gives the chest of the people they fit, from 88 to 95 cm (S) to 120 to 127 cm (XXL). Comparing a body with a half chest, without doubling, is the classic mistake.

In Ruban Size

Find my size spots half measurements by their header ("half", "flat", "laid", "pit to pit", "width" next to the measurement's name) or by their size: on an adult chart, a chest under 72 cm is read as laid flat. It doubles them, then adds room for the garment and the fit chosen. On a woven shirt chart with these values, a 96 cm chest plus 11.6 cm of regular ease is 107.6 cm, an M; Loose makes it 112.7 cm, an L. Shoppers read "This chart gives the garment's own measurements: we added room for the fit you chose."