I am planning (suggesting) an update on one of our college classrooms. I want to add laptop power availability. How many per 20 amp circuit.

I'd assume 100-150 W per laptop and limit the circuit to 80% of 20 A. That's 0.8 *20 A * 120 V or 1920 W.

At 100 W, about 19. At 150 W, it's 13 laptops. In commercial establishments there are limits to the number of outlets on a circuit.

You could be using:

1. surge suppressors with multiple outlets
2. Integrated power modules for desks with say phone, ethernet and power.
3. Floor outlets