# How to calculate RPM from a square wave signal Voltage-Time graph

I'm struggling to understand how to show the relationship between the input and output of a hall effect sensor used as a wheel speed sensor through mathematical expression. How can I calculate the RPM if the input gives me a square wave signal? I understand it may be through calculating the frequency, but I feel like I'm missing something.

$$RPM = 60 \times rps = 60 \frac 1 t \frac 1 n$$ where rps = revolutions per second.
$$RPM = \frac {60}{tn}$$