The convert(expr, 'units', unitFrom, unitTo) command multiplies the value u by the conversion factor from unitFrom to unitTo.

The units unitTo and unitFrom can be labeled in any way accepted by the Units package, for example, name, abbreviation, or symbol.

For the second calling sequence, exprWithUnit can be any expression with a unit attached in any valid way.  This can be, for example, 3*Unit('cm') or an expression with a unit added from the Units palette.

Notes: 

To enter a unit in 2-D Math input, select the unit from the appropriate Units palette. If the unit you want is not there, select $\mathrm{unit}$ and then enter the unit.

When you edit a unit, double brackets appear around it.

Note: Thermodynamic temperature conversions are for temperature intervals, not absolute temperatures. For example, 1 degree Celsius is converted to 1 kelvin, not 274.15 kelvin.  For conversions of absolute temperatures, use convert/temperature.

You can modify the properties of the conversion by including options opts. The opts argument can contain one or more of the following equations.

'energy'=true or false

If this option is set to true, the conversion can be between energy units, not necessarily units with the same dimensions. Furthermore, unitTo can be set to $1$ to convert to a dimensionless quantity.  For more information about energy transformations, see Energy Conversions.

'symbolic'=true or false

This option specifies whether annotations to units should be ignored.  By default, this option is set to false.

$\mathrm{convert}\left(100.0\,'\mathrm{units}'\,'\mathrm{ft}'\,'m'\right)$

$30.48000000$

$\mathrm{convert}\left(46145\,'\mathrm{units}'\,'\mathrm{yards}'\,'\mathrm{kilometers}'\right)$

$\frac{10548747}{250000}$

$\mathrm{convert}\left(120\,'\mathrm{units}'\,'W'\,'\mathrm{hp}'\right)$

$\frac{2000000000000000}{12428331193037837}$

$\mathrm{convert}\left(1\,'\mathrm{units}'\,'\mathrm{permittivity}\left[\mathrm{Atomic}\right]'\,1\,'\mathrm{energy}'=\mathrm{true}\right)$

$1$

$\mathrm{convert}\left(5\mathrm{Unit}\left(Nm\left(\mathrm{radius}\right)\right)\,'\mathrm{units}'\,Nm\,'\mathrm{symbolic}'=\mathrm{true}\right)$

$5⟦Nm⟧$

$\mathrm{with}\left(\mathrm{Units}\left[\mathrm{Standard}\right]\right)\:$

$3\mathrm{Unit}\left(\frac{'\mathrm{kg}''m'}{'s'}\right)$

$3⟦\frac{\mathrm{kg}m}{s}⟧$

$\mathrm{convert}\left(\,'\mathrm{units}'\,\frac{'\mathrm{lb}''\mathrm{ft}'}{'h'}\right)$

$\frac{450000000000000}{5760623099}⟦\frac{\mathrm{lb}\mathrm{ft}}{h}⟧$