Tachometer calculation

Hello and thanks always

I am building a tachometer based on a series of pulses using a PIC18F2550
I am thinking how to calculate this and so far I have this reasoning.

If the period of a pulse is period and a revolution is completed in say 6 pulses, the period of a revolution is period*6

This period in minutes would be (period*6)/60

Now one the RPM would be RPM=1/((period*6)/60) or 60/(period*6)

Is my calculation correct???


However I found this...

Tachometer calculation