A general rule of thumb for straight or slightly wavy hair is the finer the hair, the shorter it would be cut and the coarser the hair, the longer you should leave it. This is because finer hair bends easier than coarse hair and need less length to bend and lie where it should. Coarser hair needs to be longer because it does not bend as easily and needs more weight (from length) to bend and lie in place.
A basic guideline would be -
- Fine Hair 1 - 2 inches
- Medium Hair 1 1/2 - 2 1/2 inches
- Coarse Hair 2 - 3 inches
This is just a general guide, though, and each specific haircut needs to be unique for a particular person's needs.
If you are not really sure about the texture of the hair you are cutting and want to know for certain that you will be cutting it the right length, do this simple test. Cut off one hair from the top of the head right at the scalp. Hold that hair between your thumb and y our pointer finger right at the "root" end. Hold it straight up. Cut little bits of length off of the end until the hair has just a slight bend at the end. (When it's too long, it will lie down, bending close to your fingers.) Once you find the optimal length, measure that strand of hair with a ruler.
Look closely at the way the hair grows at the top of the head. If your client's hair grows straight out of the scalp (usually only 1% of people have this), then cut his hair to the length that you measured the strand of hair to be. However, if your client's hair grows at a 45 degree angle from his scalp (which is much more common), you should subtract 1 inch from the measured hair strand length.
When you have a client that has his hair thinning on the top, cut it 1/2 to 3/4 inch shorter than what you calculated from your cutting test. Thinner hair lies flatter because it doesn't have much hair around it to support it. Thinner hair (up top) will have more fullness when you cut it shorter.
