Rack Gear Pitch distance?

Issue: Need to accurately measure the pitch distance of a rack gear, without the mating gear or specs for the mating gear.

How can I accurately measure the pitch distance? Will measuring the bottom of the part, to the top of the teeth minus half of the tooth height give me the pitch distance?

Seems like that is just too simple... after much googling and reading without any clear answers... I'm turning to reddit. Any resources you can provide that will backup my thought process would be greatly appreciated!