Length

The metre is the standard of length, which is divided into 100 centimetres,
also into 1000 millimetres. 1000 metres is the same as 1 kilometre.
And we can also see that 10 millimetres is the same as 1 centimetre.

These distances can all be abbreviated to 1 or 2 letters for ease of use, especially in writing. A table of these measures is shown below:

Height is the same as length, but measured vertically. Heights can be measured in centimetres, metres and kilometres. And from length we get speed, which is length per unit time, e.g. kilometres per hour. Click here for speed info page.

Here are some examples of items and their lengths/heights shown in metric units; at least some of these things you have probably encountered, the metric dimensions will help provide a feel for such sizes as 90 mm or 100 metres:

	Floppy disk: 90 mm / 9 cm
	Compact disc: 120 mm
	Credit card: 85.5 × 54 × 0.8 mm
	Matchstick: 2 mm wide
	Football pitch (soccer): 100 metres long Every full-sized soccer pitch must be between 91-119 metres long, and between 46-91 metres wide.
	Average computer monitor, viewable screen size measured diagonally, on CRT monitor: 41 cm (Tube size is larger)
	Height of the Eiffel Tower: 300 metres
	Original height of the Great Pyramid of Giza: 147 metres
	Height of the Empire State Building: 448 metres
	Height of average British man: 176 centimetres
	Height of average British woman: 162 centimetres
	Average length of new born baby: 50 centimetres
	London double-decker routemaster bus: approx 8.4 metres long, 4.4 metres high, 2.4 metres wide. Modern London buses vary considerably in length, height and design.

United Kingdom coins

£1 coin Diameter: 23.03-23.43 mm Thickness: 2.8 mm Mass: 8.75 g	£2 coin Diameter: 28.4 mm Thickness: 2.50 mm Mass: 12 g	50 pence coin Diameter: 27.3 mm Thickness: 1.78 mm Mass: 8.0 g
20 pence coin Diameter: 21.4 mm Thickness: 1.7 mm Mass: 5.0 g	10 pence coin Diameter: 24.5 mm Thickness: 1.78 mm Mass: 6.5 g	5 pence coin Diameter: 18.0 mm Thickness: 1.0 mm Mass: 3.25 g

(coin images and data from the Royal Mint website)

If you are interested in the smaller sizes, have a look at the interactive animation at http://www.cellsalive.com/howbig.htm which will even show you nanometres.

Distance

Distances between cities, for runs, marathons, and longer distances can be measured using kilometres. As we see above, one kilometre is 1000 metres in length.

Some distances in kilometres:

Location from/to	Distance	Notes
Circumference of the Earth through the poles	40 000 km	This is what the metre was originally based on, but due to slight inaccuracies the exact distance is slightly different (actual length varies according to which website you look at).
Circumference of the Earth around the Equator	40 075 km	Distance around the Equator is slightly more due to the bulging of the Earth
Length of Great Britain	1000 km	One tenth of the distance from the North Pole to the Equator
Length of coastland of Great Britain (mainland only)	17 819 km
National Grid squares	100 km by 100 km	Ordnance Survey in the UK produces all the official maps of the country, and divides the country into 91 grid squares, each with two letters, and covering a distance of 100 km on each side of the square. Using this grid and its subdivisions, any place in the UK can be described using its grid reference. More info. The grid is divided smaller into 10 km and 1 km grid squares. The OS has been using this metric grid since the mid 1940s.
Astronomical Unit	149 000 000 km	The average distance between the Earth and the Sun, 149 million kilometres.
Light Year	9 460 000 000 000 km	The distance travelled by light in one year, 9 trillion 460 billion kilometres.
Minimum height of a mountain in England, Wales, Ireland	610 metres	This is the definition of what constitutes a mountain. If it is smaller than this height, it is not a mountain. Scotland has different classifications.
Typical altitude of airliner	11 km
The edge of space	100 km	The Ansari X Prize was won by SpaceShip One when it reached the edge of space twice.
Distance to the Moon	From 356 371 km to 406 720 km	The Moon’s orbit is elliptical so the distance varies
Marathon	42.195 km	The official marathon length, however some running races called marathons may be different distances, such as 40 km, 50 km, and is estimated to have been originally 34.5 km in ancient Greece.
UK distances	Measured as a straight line, not road distances	Road distance using most likely route
London-Manchester	263 km	325 km
London-Edinburgh	534 km	663 km
London-York	280 km	340 km
London-Newcastle	398 km	459 km
Manchester-Edinburgh	281 km	359 km
Total length of motorways in Great Britain		4353 km
Total length of A roads in Great Britain		48 164 km
Total length of B roads in Great Britain		30 216 km