How many boxes of hair dye do you need for shoulder length hair? Buy two boxes of hair dye
If your hair is past your shoulders, or shoulder-length and extremely coarse, use two boxes of the same shade to ensure full coverage. Just make sure to mix the dyes in a glass or plastic bowl — a metal one will oxidize the dye and cause it to change color.
How many tubes of hair dye do you need? The average person will probably need 2 bottles of dye for their hair. If you have what you would consider to be more than average hair in length or thickness then adjust accordingly.
Is 1 box of hair dye enough? Hair color will stain just about anything it touches (even the semi-permanent stuff). Purchase two boxes of color if your hair is long or very thick to ensure that you get even coverage. If you don’t use the second box, you can always return it or use it next time.
How long does a box of hair dye last? Hair dye boxes typically don’t have expiration dates. However, most manufacturers indicate that hair dye has a shelf life of about 3 years.