Units and Conversions
A very handy functionality are equations with units and conversions between them.
Simply treat the value with unit as any other number:
$1  2 * 1 km

If you want to convert from one unit to another, there's nothing easier:
$1  1 km to m
 
$2  10 miles/second in km/h

You can even do both at once!
$1  2 * 1 km in m

Don't worry about complicated equations with mixed units.
$1  5 *(2m + 1 km) + 28cm in m

Or even mix dimensions! Here we're mixing lengths and area without any problem:
$1  2cm * 2cm + 12cm^2

Helpful constants are ready to simplify your equations:
$1  speedOfLight to km/h
 
$2  speedOfLight to miles/s

If you go way too crazy, don't worry, calcul.io will warn you:
$1  speedOfLight to miles
