Perfect Suit Sleeve Length
The perfect suit sleeve length of a jacket should end where the inner bone of the arm ends (the radius bone). Also, it’s proper for some of the shirt sleeve to be showing past your jacket sleeve. This adds to the over-all look of the outfit, and lends further opportunity to display the color or print of the dress shirt you are wearing. It’s also an important style element when a gentleman is wearing a French cuff with attractive cuff links.
There is a general rule for the amount of cuff that should be visible, and for the classic dress suit that is well tailored, a ½” is recommended when arms are resting at your sides. The shirt sleeve should end just where the palm begins. The shirt cuff should wrap around your wrist with enough space to place a finger from the other hand inside without a struggle. It’s also important to remember that no two arms on an individual are the same length, and custom tailoring will accommodate for this.
The same rules that apply to a suit jacket also apply to a sport coat to maintain that sharp gentlemanly appeal and look of a perfect fit. Albeit, a more weekend casual wear feel to it, the rules still apply and should be adhered to.
When you receive a new jacket, be sure it is pressed and has been hanging for a few hours before judging the sleeve length for any adjustments, as this will make a difference in how it hangs.
Also, if you purchase a jacket that has less shoulder padding than normal, sometimes, depending on the fabric, it has to be slightly shortened; but you will only know once you have worn and “tested” it. Having a sleeve shortened is an easy fix and is worth it.