Tons were a unit of measurement used by humans. They could be separated into metric tons and imperial tons.
Robbie was capable of destroying two tons of granite, (COMIC: Doctor Who and the Robot) Soarers could lift up to ten tons. (PROSE: Peril in Mechanistria)
Sabalom Glitz estimated the black light converter on Ravolox at "a couple of tons". (TV: The Mysterious Planet)
According to Joel Shaw, the neutronic power unit could produce enough energy to melt "thousands of billions of tons of ice". (COMIC: Flood!!!)
The Seismosaurus weighed over a hundred tons and the Edmontonia weighed over four tons. (PROSE: Blood Heat)
Roz Forrester once crushed an N-Form to death with a million ton sheet of dwarf star alloy before it could destroy Fury. (PROSE: So Vile a Sin) Sekor Dom Sloathe was crushed with a ten ton weight when it was no longer useful. (PROSE: Sky Pirates!)
The Keratin planned to boil away the Earth's oceans and reveal millions of tons of gold in the process to aid them in their conquest of the universe. They were defeated by Sarah Jane Smith. (AUDIO: The Glittering Storm)
Milo Clancey deployed two tons of copper needles from the LIZ 79 to immobilise Ian Warne's spacecraft, which was about to fire a missile at him. (TV: The Space Pirates)