You can use the linked tire pressure Google Doc to calculate pressures for different kinds of bikes. Put in your weight and tire width, and it gives you the optimal pressure for Road, Cross, Mountain Bikes, Low-trail randonneur bikes, Fat Bikes and Triathlon bikes.

Bicycle Tire Pressure Calculator doc

You can fudge the numbers based on your experience, tire casing, riding style, and road surface.  More info about the pressure calculator.

There is also an Android app available. You can save your bikes and easily access them later. You can even do custom calculations for cargo bikes, which the doc doesn’t do yet.

From Dave Adams, trimmed down to a Google Doc by me. Based on research by Frank Berto, as published in Bicycle Quarterly.