Let’s start from the basics in case there are any women planning on helping their men trim facial or head hair. Haircut numbers refer to clipper guard sizes, and you can find the number etched into the guard itself. Most clipper sets provide 8 guards, and each hair clipper size represents the amount of hair that will be left when used. The larger the number, the longer the haircut. Oftentimes, most brands like Oster, Wahl, and Andis use increments of 1/8 of an inch.
For example, asking for a “Number 2 Haircut” means the #2 guard will be attached to the clipper to leave 1/4 inch of hair on the scalp. Similarly, a “Number 1 Haircut” is a very short cut that corresponds to a 1/8 inch length; a “Number 3 Haircut” cut to 3/8 inch; and a “Number 4” is the medium length of 1/2 inch. In this way, a man can request a Number 0, 1, 2, 3, 4, 5, 6, 7, or 8 haircut, where a “Number 0” means no guard is used, resulting in a near-shaved look with 1/16 of an inch of hair left.
Here are the haircut numbers and their respective clipper guard sizes (lengths):
A “Number 0 Haircut” has no guard attached and therefore uses the permanent guard attached to the clipper for a short cut. A zero is often used to provide a very short buzz cut or almost skin fade, leaving the scalp exposed.
A “Number 1 Haircut” is about 1/8 of an inch, which is a little longer than a number zero. The #1 guard is still ideal for buzz cuts, or you can use it to taper or fade from different numbers. However, we do not recommend a number 1 cut if you don’t want your scalp to show.
The “Number 2 Haircut” is one of the most popular clipper sizes for fade haircuts. Not too short or long, the #2 gives you 1/4 of an inch in length, allowing for a fuller hairstyle that doesn’t expose the scalp. A number 2 is a safe bet for guy’s with thinning hair and is likely perfect for thick hair.
The “Number 3 Haircut” cuts your hair down to 3/8 of an inch, and is generally the longest clipper size most barbers will use to maintain short faded sides. On the other hand, a #3 can also be used on the top for a longer buzz cut style (e.g. burr cut).
A “Number 4 Haircut” leaves hair 1/2 inch long, making it the medium length of the clipper guards. With the #4 size, you can start to get a brush or crew cut, which are similar to a buzz cut but include a skin fade on the sides and longer hair on top. The number 4 works well for both thick and thin hair.
The “Number 5 Haircut” length is 5/8 of an inch, although most brands use the #5 and #6 clipper guards for taper styling.
The “Number 6 Haircut” is 3/4 inches long. As mentioned above, the #6 size is reserved for tapering your hair.
The “Number 7 Haircut” is a 7/8 inch long cut. Because of its length, the #7 may be used to style a crew cut for men with thick hair. However, just remember to use a smaller size guard (e.g. #1, 2, 3, and 4) to fade your hair on the sides.
Finally, the “Number 8 Haircut” is one inch in length and represents the longest clipper size made in the United States. While not commonly used to give a fade haircut, the #8 is a lazy way to trim the hairs on top of your head while using a #1, 2 or 3 on the sides.
For more information on cutting your own hair, check out our reviews of the best hair clippers for professional and home use.