The following units can be choosen. If a conversion can't be found the function will return NA.
ll{
unit description
a year (assuming 365.25 days per year)
AA 1 angstrom = 100 pm
atm atmosphere (standard)
bar bar
cal calorie
C Celsius
d day
eV electronvolt
F Fahrenheit
ft foot = 12 inches
g gram, the SI unit of mass (although the definition is based on kg)
gal U.S. Gallon
h hour
hp horsepower (metric)
in inch (strangely, some people still use these)
J Joule, the Si unit of energy
l litre
lb international avoirdupois pound
m metre, the SI unit of length
m3 cubic metre
mi mile = 5280 feet
min minute
oz ounce
Pa Pascal, the SI unit of pressure
psi pound-force per square inch
s second, the SI unit of time
tn metric ton
toe 1 toe = 1000 kgoe = 1000 kg * 35 MJ/kg = 35000 MJ (energy as tons of oil equivalent)
ton metric ton
W Watt, the SI unit of power
Wh 1 Wh = 1 Wh * 3600 s/h = 3600 Ws = 3600 MJ
yd yard (basic unit of length)
}
All the details can be found in the d.units data.frame.