There are three main factors that separate an off-the-rack suit from a custom suit and they are fit, construction and customization.
1.) Fit
Off-the-rack suits are cut from a generic pattern that is made to “fit” the masses. Obviously, not all of our body types are the same and the most important aspect of a jacket is having the correct shoulder structure. Usually, patterns run in basic shoulder, chest and length sizes. One of the issues most people face is that a 40R jacket likely won’t fit the same on someone who is 5’6” versus someone who is 6’.
When purchasing a custom suit, the first thing a tailor identifies is your personal shoulder structure along with taking a very specific set of measurements. From these measurements, a suit pattern is created and then the suit fabric is cut based upon your established pattern. This process is called bespoke, which allows the suit to fit and mold to your body properly.
2.) Customization
When deliberating between a bespoke and off-the-rack suit, one huge difference is the capability of customization. The bespoke process allows you to have complete control over the final design and look of your suit. It gives you the opportunity to design the cut of your suit, the lapel width, the pocket style and even the buttonhole stitching color. When purchasing an off-the-rack suit, what you see is what you get. You have zero capabilities to design the look of your suit, and ultimately you are stuck with whatever is available for better or worse.
3.) Construction
The canvas of a suit is usually one of the most significant ways to distinguish a custom suit from an off-the-rack suit. Canvas is the skeleton of the jacket and it provides the signature structure and drape of a suit jacket. All off-the-rack suits fuse/glue the canvas to the suit fabric. The problem with this is that over time, the glue will come undone from dry cleaning and you will begin to notice bubbling and rippling in the lapel. Fusing also seriously compromises the drape of the jacket. When a suit is bespoke, the canvas is hand sewn into the jacket allowing the drape to flow properly and eliminating any potential for rippling.