Metre

A metre was a unit of length, roughly equivalent to a yard. (AUDIO: The Beast of Kravenos)

Unitary comparisons
A nanometre was a thousand millionth of a metre. (TV: Four to Doomsday)

4000 metres was equivalent to nearly 3 miles. (AUDIO: The Screaming Ceiling)

Known measurements
When fused together, the float-stones allowed the platform structures of the Karagulans to float about half a metre above the surface of Karagula. (PROSE: The Colour of Darkness)

The Eight Legs were generally less than a metre in length, though the Great One was much larger. (TV: Planet of the Spiders)

Both Cimmerians and Solarians stood about one metre tall. (AUDIO: Embrace the Darkness) The Pakhars, too, were only a metre tall when standing upright. (PROSE: Legacy)

The Zolfa-Thurans reached around 1.5 metres tall. (TV: Meglos)

The Mantodeans grew up to two metres long. (PROSE: Winner Takes All) Judoon were also two metres high. (TV: Smith and Jones) Icarus Falling's bulkheads were constructed of two metres of Iron, steel and reinforced kevlar, all of which the Daleks are able to get through in 28 minutes. (COMIC: Fire and Brimstone)

Larvae guns measured approximately two metres in length and half a metre high. (TV: The Web Planet)

The Beserkat Felines, (PROSE: The Doctor Trap) and Drudges, stood 2.5 metres tall. (PROSE: Lungbarrow) The Dominators were over two and half metres tall. (PROSE: The Dominators)

John Crichton was a British athlete who jumped 2.6362 metres in the Olympic Games. (TV: Invasion of the Dinosaurs)

The Chakra were three metres tall. (PROSE: The Pit) The Megalosaurus (PROSE: The Last Dodo) and adult Vespiforms, were around and three metres in height, (TV: The Unicorn and the Wasp) and the walls of the Flydon Maxima Research Base were three metres thick. (PROSE: The Depths of Despair) The Veltrochni were up to three metres tall. (PROSE: The Dark Path)

Adult mayflies could reach several metres long, (TV: Reset) as could Sky sharks. (TV: A Christmas Carol)

Sundayan 'gators were approximately 5 metres in length. (PROSE: Wetworld) An adult Drexxon was roughly five metres tall. (PROSE: Death Riders) The Cybershades could jump at least five metres off of the ground. (TV: The Next Doctor)

The Steller's sea cow could be as much as eight metres long. (PROSE: The Last Dodo)

Branzine mining by the Halflings on Juno 10 created a twenty metre wide hole in the process. (PROSE: Penny Wise, Pound Foolish)

Kaldarean bedmites were on average thirty metres in height at birth. (TV: The Last Precinct)

The Raab could grow up to five hundred metres long. (PROSE: Frontier Worlds)

Doctor Who Adventures
Doctor Who Adventures magazine gives details on the heights of several species and other elements in the DWU.
 * DWA 98, DWA 106: The CyberKing stands 60 metres tall, Bannakaffalatta stood only 1.1 metre tall and the Macra on New Earth 20 metres.
 * DWA 175: The real stones at Stonehenge stand seven metres tall and are over 2000 years old. Replica stones only three metres tall were made in two weeks of fibreglass on wooden frames and referred to by the crew as 'Foamhenge'. These were used to film all of the Doctor's speech scene. (TV: The Pandorica Opens)
 * DWA 225: Sontarans stand 1.5 metres tall.
 * DWA 196: Heights (in metres): Adipose 0.15, Bannakaffalatta 1, Cybermen 2.15, CyberKing 61, Daleks - Bronze Daleks 1.8 new Daleks 2, Eleventh Doctor 1.82, Krafayis 3 and Sontaran 1.15
 * DWA 150: Cybermen are all the same height – 2 metres tall.

Doctor Who: Battles in Time

 * According to non-narrative information in DWBIT 9, the Squeeth had metre-long incisors.
 * According to DWBIT 23, adult Nidilla were capable of weaving webs up to twenty metres across, coated with a sticky substance similar to superglue.