Unless otherwise defined by the GM, a world is assumed to have gravity similar to Earth's.

A creature can fall up to 5 feet without taking any damage, or adverse effects.

A creature that falls greater than or equal to 10 feet falls Prone.

After 10 feet or greater, the creature takes d6 Bludgeoning damage. For each 10 feet there after the die size increases by its standard increment (d8, d10, d12, d20).

Example:
- 10 ft. to 20 ft. = d6
- 20 ft. to 30 ft. = 2d8
- 30 ft. to 40 ft. = 3d10
- 40 ft. to 50 ft. = 4d12
- 50 ft. to 60 ft. = 5d20
Add a d20 to every 10 feet beyond that....

The GM of course can modify these gravity worlds in other Planes of existence.

Balance is a Skill that can help with Falling Damage.