Physical quantities have both numbers and units, and each
physical quantity should be expressed as the product of a
number and a unit. Typesetting physical quantities requires
care to ensure that the combined mathematical meaning of the
number-unit combination is clear. In particular, the SI units
system lays down a consistent set of units with rules on how
these are to be used. However, different countries and
publishers have differing conventions on the exact appearance
of numbers (and units). The siunitx package provides a set of
tools for authors to typeset quantities in a consistent way.
The package has an extended set of configuration options which
make it possible to follow varying typographic conventions with
the same input syntax. The package includes automated
processing of numbers and units, and the ability to control
tabular alignment of numbers.

Homepage:
https://ctan.org/pkg/siunitx
