While most people tend to group military haircuts into just one category, in this case "short," each branch of the American military has distinct standards that men in uniform are required to meet. The following summarizes the military hairstyle regulations for the United States Army, Navy, Air Force, and Marine Corps.
The hair must be neat, clean, and well groomed in appearance. The hair above the ears and at the nape of the neck must be tapered. A block at the neckline is permitted with a tapered appearance. Hair may not touch the ears, eyebrows or collar (except that the closely tapered hair at the neck may touch the collar). The length and bulk of the hair may not interfere with properly worn headgear.
Male haircuts must conform to standards. The hair on the top of the head must be neatly groomed and may not be trendy, spiky or disheveled in appearance. The hair must be tapered and conform to the shape of the head and the neckline must be tapered. Hair must not be allowed to fall over the ears or touch the collar (except that the taper at the neckline may extend past the collar). A classic taper or Ivy League haircut is normally the style of choice for most soldiers in the United States Army.