Our standard (S/M/L/XL/XXL) sizing is very similar to familiar brands such as Polo Ralph Lauren, Eton, and Uniqlo. If you fit any of those shirts, you should be quite comfortable in the same letter sizing under our name.
Our neck and sleeve (custom) sizing is great for those who know their preferred neck and sleeve (16 x 34, for example) and know what type of fit they prefer. Our allowances are similarly in line with those provided by the three major brands above. If you normally wear Brooks Brothers, we recommend picking one fit allowance higher, because Brooks Brothers tend to run large by industry standards.
If you aren't happy with off the rack shirts, we always offer full bespoke tailoring as well.