A Wortham unit was a unit of measurement of energy.

In 2267, Montgomery Scott reported that the power generated by Vaal totalled 100 to the 20th power Wortham units. (TOS episode: "The Apple")

In 2269, Pavel Chekov, while in high-gravity conditions, "put the last Wortham unit of energy he had" into altering the Queen Mary's gravity, thus incapacitating Krulmadden and his crew. (TOS novel: Prime Directive)