-- Units in CalcPad are specified in pretty much the same way as any textbook.  For example:

34 kg m/sec^2

-- The above is 34 kilogram-meters per second squared.  Since CalcPad has a predefined unit (N) that matches these dimensions, you could also simply enter:

34 N

-- You can use any symbol like a unit, but to let CalcPad know that a symbol is meant to be used that way, add the "unit" directive:

unit inch = 2.54 cm
unit ft = 12 inch

-- Then, you can enter values in terms of "inch" or "foot".  As a variation of this, add "metric" to specify that a unit should get all the standard metric prefixes.  Although it's silly, you could do

metric unit ft = 12 inch

-- ...and now be able to use "kfoot" to mean 1000 feet, or "mft" to mean 0.001 feet (a millifoot).

--  On input, it doesn't matter which units you use to specify the values you have in mind.  On output, what is displayed is controlled by a list of "preferred units" kept with the document.  (See "Built-In Units" in the Help menu for the default list.)  You can tell CalcPad that you prefer to see certain units in either of two ways.  One way is to use the "in" operator:

3 m in inch

-- The above says, show me the value "3 m" using the unit "inch" as much as possible.  This works even when you don't have an exact match, for example:

3 m/sec in inch

-- You can also specify multiple units, like so:

0.3 cm/sec in inch, min

-- ...which would show you this speed in terms of inches per minute.  The other way to change your unit preferences is via the "use" keyword, for example:

use nauticalMile, bar
926 m

-- This tells CalcPad that you want to see nauticalMiles and bars in your results where applicable.  It does exactly the same thing as "in" but doesn't require an expression; it only affects subsequent expressions in the same document.
