{siunitx} is a package that provides consistent typesetting of physical quantities, allowing application of various typographic conventions with the same input syntax. This package replaces the deprecated {siunits} package.

siunitx is a package that provides consistent typesetting of physical quantities (in SI units and their derivatives). Adjusting the package options allows following a specific non-standard set of typographic requirements with the same input syntax.

The package processes numbers and units automatically, and provides a column format for aligning numbers and units in a table.

The package is a successor to , which now has few uses and is widely considered to be obsolete.

Basic usage

The package provides the following typesetting macros:

  • \num[<options>]{<number>} for numbers,
  • \ang[<options>]{<angle>} for angles,
  • \si[<options>]{<unit>} for units,
  • \SI[<options>]{<number>}[<pre-unit>]{<unit>} for the combination of numbers and units,
  • various …list and …range variants.

The macro \sisetup can be used to change settings globally.

For tables exist the column specifications

  • S[<options>] for numbers, and
  • s[<options>] for units, and also
  • a \tablenum[<options>][<number>] macro that mimics the functions of the S column.


The siunitx package is hosted by CTAN as package http://ctan.org/pkg/siunitx and is developed by Joseph Wright, who provides news about the packages plans and progress at his weblog.