Follow these straightforward moves toward sorting out size measurements: Measuring T-Shirt Size:  Tshirt Chest - Measure around the body under the arms at the fullest part of the chest with your arms relaxed at two sides. Tshirt Height - Measure from the shoulder crease through the t-shirt bottom. Sleeve Length- Measure the length from shoulder crease upto the sleeve end. *** the size of the garment may vary by 0.5" from the mentioned measurements