GNU units converts quantities expressed in various systems of measurement to their equivalents in other systems of measurement. Like many similar programs, it can handle multiplicative scale changes. It can also handle nonlinear conversions such as Fahrenheit to Celsius, and it can perform conversions from and to sums of units, such as converting between feet plus inches and meters. Beyond simple unit conversions, units can be used as a general-purpose scientific calculator which keeps track of units in its calculations. You can form arbitrary complex mathematical expressions of dimensions including sums, products, quotients, powers, and even roots of dimensions. In this way, you can ensure accuracy and dimensional consistency when working with long expressions which involve many different units which may combine in complex ways. The units are defined in an extensive, well-annotated data file which defines over 2,500 units. You can also provide your own file to supplement or replace the standard file.
|Operating Systems||Windows Windows POSIX|
Release Notes: This version supports '_' to represent the previous result and support for rational exponents. Output can be logged to a file with -L. Nonlinear unit synonyms are easier to define, and display of nonlinear unit definitions now shows the range and domain and type of units needed. Error handling is better, and various bugs have been fixed.
Release Notes: This release corrects an electron mass error.
Release Notes: This release supports conversion to sums of units (e.g., feet and inches or hours and minutes). It includes a script to automatically update the currency conversion rates. The units are now in Unicode with UTF-8. Units can be defined with reference to environment variables, so you can now select local units such as the gallon without changing locale, and these units will work everywhere. The name of the units database has changed, and the syntax for defining nonlinear units has changed slightly to allow specification of domain and range. The personal units database is now $HOME/.units.
Release Notes: The units database has been updated to include the latest NIST values, abrasive grits, and other fixes.
Release Notes: Units now reads custom definitions from ~/.units.dat. The precedence of "*" has changed to match the usual algebraic precedence, and the "**" operator was added for exponents. A text search feature was added so that typing "search text" lists the units whose names contain "text".