Check for you perfect fit in the size chart below(in inches):

Person's Chest  |Shirt Size  | Ready Garment Measurement (in inches)                                 |
(in inches)    |    |     Chest           |  Sleeve Length  |Shoulder | Neck |
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 37-38  |   Small           |  42"(38+4 Loosing)     | 25    | 17.5 | 16  |
39-40  | Medium |  43"(39+4 Loosing)     | 25.5     | 18 | 16.5 |
 41-42 |   Large |  45"(41+4 Loosing)     |26  |18.5  | 17  |
 43-44  | Extra L|  46"(43+3 Loosing)     | 26.5          | 19  | 17.5  |