Calculating GPE

The distance moved by a weight must be in the direction of the force - i.e. up or down. So we can say:

Energy Transferred = Weight × Change in Height

In other words:

Change in GPE = Weight × Change in Height

Or:

Change in GPE = Mass × Gravity × Change in Height
GPE = mgh (where GPE and h are changes)

Being a form of energy, it is measured in joules (J).