Why write another unit converter? There are plenty of them out there. Well, I couldn't find one that worked quite the way I wanted. With ConvertAll, you can combine the units any way you want. If you want to convert from inches per decade, thats fine. Or from meter-pounds. Or from cubic nautical miles. The units don't have to make sense to anyone else.

ConvertAll Features:
The base units for conversion may be either typed (with auto-completion) or selected from a list.
As a unit is typed, the unit list is automatically filtered to show only units with matching words.
In general, either a unit's full name or its abbreviation can be used.
Units may be combined with the "*" and "/" operators.
Units may be raised to powers (squared, cubed, etc.) with the "^" operator.
Units in the denominator may be grouped with parenthesis.
Units with non-linear scales, such as temperature, can also be converted.
Recently used unit combinations may be picked from a menu.
Numbers may be entered on either the "From" or the "To" units side, for conversions in both directions.
Basic mathematical expressions may be entered in place of numbers.
Options control the formatting of numerical results.
The unit data includes over 500 units.
The format of the unit data file makes it easy to add additional units.
Command line options are available to do conversions without the GUI.
The user interface and the unit data are available in English, French, German, Russian and Spanish.