![](https://cdn.shopify.com/s/files/1/2574/2560/files/SL1.png?v=1631550897)
Step 1: Button the jacket and lay it flat on a table with the collar up and position the arm in a natural position. Use your hands to gently extend and flatten out excess fabric.
![](https://cdn.shopify.com/s/files/1/2574/2560/files/SL2.png?v=1631550916)
Step 2: Beginning at the top of the armhole seam (at the middle point of the shoulder) measure straight down through the middle of the sleeve to the sleeve edge.