# To display the lengths in millimeters by default [duplicate]

All my length are in millimetres and the command \the\mylength outputs a length in points. Idem with the \layout from the package layout.

How can I display all theses lengths in millimetres (more easily understandable than the points).

## marked as duplicate by egreg, Gonzalo Medina, Mico, Svend Tveskæg, Claudio FiandrinoApr 24 '14 at 14:00

• You can't do it with \the unless you change the source code of TeX and recompile it. There are other questions dealing with the problem of showing length in different units of measure. – egreg Apr 24 '14 at 12:59
• @egreg: The duplicate does not explain, how to reconfigure package layout. – Heiko Oberdiek Apr 24 '14 at 13:50
• @HeikoOberdiek I'll add it as an example application. – egreg Apr 24 '14 at 13:57

There are many ways to convert a dimen with unit pt to another unit such as mm, see How do I convert pt/in/cm/mm to em/ex as they are defined at a given point in the document?, for example.

The following document prints the layout values of package layout's \layout in mm using e-TeX:

\documentclass{article}
\usepackage{layout}

\makeatletter
\renewcommand*{\lay@value}[2]{%
\strip@pt\dimexpr0.351459\dimexpr\csname#2\endcsname\relax\relax mm%
}
\makeatother

\begin{document}
\layout
\end{document}


• Is the number 0.351459 a conversion factor purely? because google says 1 pt=0.352778 mm. – kaka Mar 28 '16 at 23:40
• @kaka TeX's pt: 1 in = 2.54 mm = 72.27 pt, conversion factor = 0.351459. TeX's bp = 1 in = 2.54mm = 72 bp, conversion factor = 0.352778. The points in PostScript or PDF are TeX's bp. TeX uses the slightly smaller points as unit for displaying lengths. – Heiko Oberdiek Mar 29 '16 at 4:42
• thanks for sharing that. I had no idea about that. – kaka Mar 29 '16 at 8:08