Whether you're a woman who plans to help a man trim his scalp or facial hair, or a man who wants to try to groom himself instead of visit a barber, you'll need to know what the numbered settings on hair clippers mean. The knowledge can also help ensure you get the type of cut you want from a professional stylist, who may ask what number you want used.
The numbers on hair clippers refer to the clipper guard, which determines how close of a cut you get. While not every hairstyle requires clippers, some cuts, such as fades or military high-and-tight cuts, do.
If the clipper is set to zero, there is no guard attached. You can't safely get an extremely close shave at the "zero" setting; it will leave as much stubble as you would have after one or two days of beard growth. While you shave your entire head this short, this setting is most often used to clean up hair around the hairline. Often, longer clipper settings are used to blend the hair.
The No. 1 attachment leaves hair an eighth of an inch long. The No. 2 setting leaves hair one-quarter of an inch long. The No. 3 attachment leaves hair three-eighths of an inch long. The No. 4 setting leaves hair half an inch long. The No. 5 attachment cuts hair to five-eighths of an inch. The No. 6 guard leaves hair at three-fourths of an inch. The No. 7 setting cuts hair to seven-eighths of an inch long, and the No. 8 attachment leaves hair an inch long.
Settings 1 and 2 leave the scalp exposed. If the hair isn't very thick, some scalp may show through on setting No. 3 as well. If you don't want any scalp to show, you should avoid these settings. However, if your hair is extremely thick, setting No. 2 may not expose any scalp. Often, these settings are used to blend short hair to longer hair. At setting No. 4, the hair looks clean-cut without showing scalp. The No. 5 setting produces a cut similar to the No. 4 setting and is often not included in traditional clipper kits but is instead sold separately.