I'm currently in the process of writing on my PhD-thesis. According to my uni's theses formatting guidelines, font size should be 13 pt. The thesis document class is set to report, which only takes 10pt, 11pt and 12pt as input.

Now, I found this solution, which seems to address my problem. I added the two suggested commands: \fontsize{13}{\baselineskip} and \selectfont, but there's no change in the font size in my document. What am I doing wrong?

If it help, I've added my document layout below. The added lines are at the beginning of %Styles.

\documentclass[12pt,twoside, openright]{report}

\usepackage[backend=biber, style=apa]{biblatex}

\graphicspath{ {images/} }


%Added lines

%Existing style commands
\fancyhead[RO,LE]{Thesis title}
\fancyfoot[LO,CE]{Chapter \thechapter}

%Thesis information
\title{Thesis Title}
\author{Author Name}

%Document start
  • As soon as something is running \normalsize your changes are gone, and that command is used al overthe place. The koma classes might have a 13pt option out of the box. The memoir class does not out of the box, but you can copy the macro file behind the 12pt option, rename it, adjust it to fit 13ptand then have memoir use that file.
    – daleif
    Feb 17, 2020 at 21:26

1 Answer 1


Koma-script allows you to set the main font to an arbitrary size, and scales the other dimensions appropriately. You can change

\documentclass[12pt,twoside, openright]{report}

to either

\documentclass[twoside, openright, fontsize=13pt]{scrreprt}

or to

\documentclass[twoside, openright]{report}

There is a fixed set of legacy options such as 10pt and 12pt, for backward compatibility. The standard document classes do not accept arbitrary font sizes: 11.5pt or 13pt do not work.

The libertine package ought to be able to handle the scaling just fine. You should, however, remove fontenc. The libertine package already loads fontspec on a modern engine, or else sets the encoding on a legacy engine. You might also consider libertinus.

  • \documentclass[twoside, openright, fontsize=13pt]{scrreprt} worked like a charm! And thanks for the other advice as well. What is the difference between libertine and libertinus? To my eye they look identical... Feb 17, 2020 at 22:14
  • I am sorry for writing an off-topic comment on your answer but I know you answer many font questions on this site. So, would you allow me to refer you to my previously asked question where I struggle with some font issue?
    – Diaa
    Feb 17, 2020 at 22:29
  • @pehkawn Libertinus is a fork by Khaled Hosny of Linux Libertine. It adds a Unicode math font and some additional alphabets.
    – Davislor
    Feb 17, 2020 at 22:29
  • @Diaa I can’t promise to get to it right away, but sure. A mod will come by later and clean the comments up.
    – Davislor
    Feb 17, 2020 at 22:30
  • If you don't mind, I have invited you to a room to explain my problem.
    – Diaa
    Feb 17, 2020 at 22:38

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