The "half-chest" or "across-chest" measurement
This reference relates to the width of the t-shirts or garments, not the body. The measurement is obtained by laying the t-shirt (hoodie, shirt or other top) flat on a flat surface. The garment is then measured across the front, side-seam to side-seam, from just a few centimetres below where the sleeve joins the body of the garment. A garment with a half or across-chest measurement of 50cm would be skin-tight on a person with a 100cm chest. Therefore, the half or across-chest measurement - when doubled - should be a few centimetres more than the person's actual chest measurement (depending on desired fit and garment stretch). Please note that we try our best to be as accurate as possible, but there may a be variance of 1-3% in our measurements.
Finding your size from the "half-chest" or "across-chest" measurement
Take a favourite-fitting garment, lay it flat, and measure across the front as described above(~1cm below the armpit). Match this measurement to the "half-chest" or "across-chest" measurement for the garment you're interested in (on the product detail page). For pre-shrunk cotton rich garments, allow 1-3% for further shrinkage. For cotton-rich and 100% cotton garments that are not pre-shrunk, allow 5-7% extra in the width for future shrinkage. This is especially important to consider for growing children. To minimise natural shrinkage, follow the care instructions on each garment carefully.