Conversions are performed by using a conversion factor. By knowing the conversion factor, converting between units can become a simple multiplication problem:
S * C = E
Where S is our starting value, C is our conversion factor, and E is our end converted result.
To simply convert from any unit into meters, for example, from 50 centimeters, just multiply by the conversion value in the right column in the table below.
50 cm * 0.01 [ (m) / (cm) ] = 0.5 m
To convert from meters into units in the left column divide by the value in the right column or, multiply by the reciprocal, 1/x.
0.5 m / 0.01 [ (m) / (cm) ] = 50 cm
To convert among any units in the left column, say from A to B, you can multiply by the factor for A to convert A into m then divide by the factor for B to convert out of m. Or, you can find the single factor you need by dividing the A factor by the B factor.
For example, to convert from centimeters to inches you would multiply by 0.01 then divide by 0.0254. Or, multiply by 0.01/0.0254 = 0.3937007. So, to convert directly from cm to in you multiply by 0.3937007.
Another way to look at it is that conversions are performed by multiplying the value to convert by the ratio of 1 input unit in meters to 1 output unit in meters. For example, to convert inch to mile: 1 inch = 0.0254 meters; 1 mile = 1609.344 meters. The ratio of 0.0254 (meter/inch)/ 1609.344 (meter/mile) = 1.5783e-5 mile/inch. The formula for converting 2345 inches to miles is [ 2345 inches * 1.5783e-5 mile/inch = 0.037011 miles ].
|To Convert from
|and Convert to
( m )
( m / Unit )
|mil (0.001 in)||mil||meter||0.0000254|
The National Institute of Standards and Technology (NIST) - The NIST Guide for the use of the International System of Units - Appendix B, subsections B.8 Factors for Units Listed Alphabetically and B.9 Factors for units listed by kind of quantity or field of science.
Lide, David R., Daniel (Editor-in-Chief). CRC Handbook of Chemistry and Physics, 89th Edition New York, NY: CRC Press, p. 1-28, 2008.
Wikipedia contributors. "Conversion of units" Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, last visited 26 Jun. 2011.
How Many? A dictionary of units of measurement at http://www.unc.edu/~rowlett/units/