# Extra 0.1cm after setting geometry top margin

I try to set 3cm for top margin of the paper with geometry package. After I measure the real length of top margin with PDF, this is actually 3.1 cm. There are a 0.1 extra space there. Also, I spot many inconsistencies with below margin. At one page it is exactly 3cm. At many pages it exceeds or lack 0.1cm from exact wanted margin.

Beside geometry, I also use fancydhr, and customize some native pagestyle. Here is my MWE.

\documentclass[12pt, a4paper, onecolumn, oneside, final]{report}
\setlength{\footskip}{0.5cm}
\usepackage{fancyhdr}
\fancypagestyle{plain}
{%
\fancyhf{}%
\fancyfoot[C]{\thepage}%
\fancyfoot[R]{\footnotesize {\fontfamily{phv}\selectfont{\bo{Dummy University}}}}
\renewcommand{\footrulewidth}{0pt}
}%
\begin{document}
Some text blah blah blah
\end{document}


Where actually bottom margin of geometry is measured from bottom side of paper? Right below 'g' or 'e'? Or--though I think it is least unlikely--it is just a flaw from pdf viewer used to measure size?

• Did you measure it on-screen at 100% zoom? Or did you print it out? If printed, remove any "fit to page margins" options of the printer. – Werner Mar 18 '14 at 14:37
• On-screen. PDF-Xchange viewer has its unique tool so user could measure any distance in one pdf document – aggy Mar 18 '14 at 14:52

The report class uses \raggedbottom, so it's normal that the bottom line is not at 3cm exactly from the bottom side of the paper. The distance is measured from the baseline, so where the “e” sits.

If you measure the top distance, you should get that the first baseline sits 3cm + 12pt (the value of the \topskip parameter). An uppercase letter is (with the Computer Modern fonts) 8.2pt high. So, if you measure from the top side to the top of an uppercase letter in the first line, you should have a distance of

3cm + (12-8.2)pt = 3.13cm

On the other hand, an integer number of lines doesn't fill 23.7cm (29.7-3-3). Let's see why: the first line occupies 12pt and successive baselines are 14.5pt apart from each other. The text block area is 23.7cm = 674.33pt high; so you can fit 46 lines, which occupy

(45*14.5 + 12)pt = 664.5pt

and so 9.83pt are missing, that is 0.35cm (in a page where only continuous text is typeset, no title or other object).

If you add the showframe option to the call of geometry, you get this for the top:

where you see the line where the 3cm are measured from, slightly above the “A”.

Here's a picture of the bottom:

where the missing 3.5mm are clearly visible.

Here is the result after adding

\setlength{\topskip}{8.2pt}


so the baselineskip will be 14.5*1.02=14.79 and

14.79*45 + 8.2 = 673.75

(which is just 0.58pt from 674.33pt = 23.7cm). Top:

and bottom:

I wouldn't bother, though.

• An uppercase letter is (with the Computer Modern fonts) 8.2pt high. I think when I'm setting the size to 12 or 14 pt it will be 12 or 14 pt too. For uppercase, it's just a slight enlargement to, such as 12.1 or 14.2 pt. – aggy Mar 21 '14 at 13:06
• @aggy I did the measurement with a 12pt font size. – egreg Mar 21 '14 at 13:08
• \topskip = font size? – aggy Mar 21 '14 at 13:56
• @aggy Usually so. – egreg Mar 21 '14 at 13:58
• OK. How about \singlespacing, \onehalfspacing. What is their connection with \linespread? Thank you very much for the answer. This enlights. – aggy Mar 21 '14 at 14:39