Distance
1 inch	= 2.54 centimeters	= 25.4 millimeters
1 foot	= 0.305 meter	= 30.48 centimeters
1 yard	= 0.9144 meter
1 mile	= 1.61 kilometers	= 5,280 feet
1 kilometer	= 1,000 meters	= 0.6214 mile
1 meter	= 100 centimeters	= 1,000 millimeters
1 meter	= 3.28 feet
1 centimeter	= 0.3937 inch	= 10 millimeters
1 millimeter	= 0.039 inch	= 0.1 centimeter
1 micron	1 micron	= 10 meter
10-6 meter	= 1 micrometer

Weight
1 kilogram	= 1000 grams	= 2.2 pounds
1 gram	= 1,000 milligrams	= 1,000 milligrams
1 milligram	= 1,000 micrograms	= 1/1,000 gram
1 microgram	= 10-6 grams	= 1/1,000 milligram
1 nanogram	= 10-9 grams	= 1/1,000 microgram
1 pound	= 0.45 kilogram	= l6 ounces
1 ounce	= 28.35 grams

Volume
1 kilolitre	= 1,000 litres	= 1 cubic meter
1 litr	= 1,000 millilitres	= 1,000 cc
1 millilitre	= 1 cc (exactly 1.000027cc)
1 fluid ounce	= 29.57 millilitres
1 US gallon	= 3.785 litres
1 imperial gallon	= 4.546 litres