How to Measure a Shirt
Take a shirt you like and that fits you well. Measure it following the pictures below.
1. Chest. Button the shirt up and spread it out on a flat surface. Measure the width across the chest from one side seam to the other.
2. Neck. Open the shirt so that the collar lies flat. Start measuring from the inside point of the button band (this part will be underneath the buttonhole band and therefore it would be a duplication to include the width of the button band.) Measure to the far right edge of the collar which will include the width of the buttonhole band
3. Back-neck to bottom. Measure from the centre bottom of the collar down the centre of the shirt back to the point at the bottom of the shirt–the length you want the shirt to be at the hips.
4. Sleeve length. Stretch out the sleeve and measure from the top where it meets the body of the shirt, down to the end of the cuff–the total length the sleeve needs to be. If you want short sleeves, measure to where you want the sleeve to end.