Why does the calculator divide the stages into fractions?

Last updated on September 24, 2020


Hello again,

I think I messaged you a few weeks ago about the Tanner Calculator. Last time I got a 1.8 or 1.9 and I was confused because I already had pubic hair. I got my first hairs about 4 months ago and recently spectacular things happened to my body. I have started to get pimples near my hairline, but I thought this wasn’t supposed to happen until Stage 4! Also, I gained the ability to ejaculate semen last week. My Tanner Stage is now 2.5. My questions are:

  1. Why is stage one divided into points on the calculator? If there are no changes present before stage two, then how is there a way of telling where you are in stage one??
  2. Why am I getting acne in stage two?

I hope you get back to me soon and thanks in advance.


Puberty is technically defined as the time when your hormones rise in your blood. For boys, this happens about a year before external signs of change are noticed. The divisions prior to stage 2 are mostly based on age. The calculator, though, tends to lean toward wanting to have multiple indications that you are in a certain stage. Therefore, a 1.8 or 1.9 says you are of the age that you should be seeing signs soon or that the signs you are seeing are not definitive enough to say you are in stage 2. I did make some adjustments to the lower end of the calculator’s scale.

Acne can come at any time. Likely you had a spike in hormone production recently that caused your oil glands to overproduce. The result is a few pimples, which should be manageable by washing more carefully. When you get to stage 4 you will find the outbreaks then will make your current acne seem like nothing. In addition, when hair follicles change from vellus to terminal, they often will raise a red bump for a little while. It is easy to mistake new terminal hairs for acne.