Metric Units Conversion Calculator
Convert among units for any base unit of measure such as gram or meter or second or byte, etc.
For example, if you want to convert from meters to micrometers you would convert from "base unit" to micro. Likewise, if you want to convert from grams to micrograms or feet to microfeet you would still do a conversion from base unit to micro. Similarly, converting from kilograms to nanograms you just need to convert from kilo to nano.
For further reading on SI Units please see Wikipedia for The International System of Units and SI Prefixes.