Measurement: Metric

Carats in a gram			5
Litres in a cubic metre			1,000 (10 x 10 x 10)
Kilograms in a tonne			1,000
Square metres in an are			100
Square metres in a hectare			10,000
10^–6 metres			Micron
Microns in a millimetre			1,000
Microns in a centimetre			10,000
Microns in a metre			1,000,000
10^–10 metres (one ten billionth of a metre, 0.1 nanometres, or 100 picometres)			Angstrom unit
A kilogram is defined as the weight of one litre of water at			4 °C
Ten decibels make			1 bel

The table below is all about converting metric units to imperial, and vice versa.

Litres in a gallon (Imperial)		4.54609
Litres in a US liquid gallon		3.785412
Litres in a US dry gallon		4.404884
Kilograms in a hundredweight		50.8
Metres in a yard		0.9144 (exactly)
Miles in a kilometre		0.6214
Kilometres in a mile		1.609
Square kilometres in a square mile		2.59
Pounds in a kilogram		2.205
Square miles in a square kilometre		0.3861
Kilograms to a pound		0.45359237 (exactly)
Acres in a hectare		2.471
Hectares in an acre		0.4047
Litres in a gallon		4.546
Millimetres in an inch		25.4 (exactly)
Grams in an ounce		28.35
Grams in a pound		453.6
Pints in a litre		1.76
Millilitres in a pint		568
Centilitres (cubic centimetres) in a fluid ounce		28.41