Here’s a bar chart (no pun intended) that shows the relationships of several pressure measures to eachother, using One psi as the reference:
It resulted from a discussion on another forum where adapting a gasoline generator to propane was being discussed.
These days, when I look at pressure or vacuum gauges to buy, i often see a dual scale with one of these other measures on it.
Of course there are several other pressure/vacuum measures in use, too.
Inch/ounces, torr, microns, etc…