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Beamer sets all text in a sans-serif Computer Modern by default, and fonts are changed in three separate layers: the font theme (serif or sans-serif behaviour), the font package (the actual family) and setbeamerfont (size, shape, series and family of single elements such as the frame title). This guide shows which command belongs to which layer, taken from the Beamer User Guide v3.78 (chapter 18) and read on 2026-11-07.
Which command changes what: a decision table
| Goal | Command | Layer |
|---|---|---|
| Serif text instead of the sans-serif default | usefonttheme{serif} |
Font theme |
| Serif text, math kept sans serif | usefonttheme[stillsansserifmath]{serif} |
Font theme |
| Use the real glyphs of a math font package | usefonttheme{professionalfonts} |
Font theme |
| Times for text, Helvetica for sans-serif | usepackage{mathptmx} and usepackage{helvet} |
Font package |
| Larger or smaller base size | Class option [10pt], [12pt] (and with extsizes: 8pt, 9pt, 14pt, 17pt, 20pt) |
Document class |
| One element only (frame title, title, and so on) | setbeamerfont{frametitle}{size=large,series=bfseries} |
Per-element font |
| Bold or small-caps structure elements | usefonttheme{structurebold}, usefonttheme{structuresmallcapsserif} |
Font theme |
Source: Beamer User Guide v3.78, chapter 18 (Fonts). Font themes do not choose font families; the guide states that the family is changed by loading packages (section 18.2.2).
What it is used for in research
Conference talks, thesis defences and seminar slides are commonly built with Beamer, and font changes are usually needed to match a department template, to make equations legible from the back of a room, or to make slide text match the typeface of a paper. Font choices also interact with mathematics: Beamer replaces some math glyphs internally, which matters when a journal or template requires a specific math font.
Install or access (official source only)
Beamer is distributed with standard TeX distributions and is documented on CTAN; the current user guide is the PDF at mirrors.ctan.org/macros/latex/contrib/beamer/doc/beameruserguide.pdf. Packages named below (mathptmx, helvet, lmodern, fontspec) are likewise obtained from your TeX distribution or from CTAN, or are already present on an online editor. Load them in the preamble, after documentclass{beamer}.
Step-by-step: change the font in a Beamer presentation
1. Choose the base size (class option)
The default size is 11pt. 10pt gives the smaller setting and 12pt the bigger one without any extra package. The sizes 8pt, 9pt, 14pt, 17pt and 20pt require the extsizes package to be available. The guide notes that 17pt is about the default size of PowerPoint, and that the frame is 128 mm by 96 mm and is enlarged by the viewer.
documentclass[17pt]{beamer}2. Switch between sans serif and serif (font theme)
The default font theme installs sans-serif for all text. To get serif:
usefonttheme{serif}Options of the serif theme are stillsansserifmath, stillsansserifsmall, stillsansseriflarge, stillsansseriftext and onlymath (serif math only).
3. Change the font family (packages, pdfLaTeX)
The default family is Computer Modern. The guide’s example loads Times and Helvetica:
usepackage{mathptmx}
usepackage{helvet}Without the serif font theme this selects Helvetica as the text font, because Beamer is sans-serif by default. The packages the guide lists for this purpose are arev, avant, bookman, chancery, charter, euler, helvet, lmodern, mathtime, mathptm, mathptmx, newcent, palatino, pifont and utopia.
4. Set the encoding
usepackage[T1]{fontenc}
usepackage{lmodern}The guide recommends this combination and suggests checking that ligatures such as fi come out correctly.
5. Use system fonts (LuaLaTeX or XeLaTeX)
With LuaLaTeX or XeLaTeX, Beamer can use OpenType system fonts through the fontspec package (see the fontspec documentation on CTAN). The Beamer guide recommends LuaLaTeX over XeLaTeX, and notes that with TU encoding the default is OpenType Latin Modern. The package-based commands in step 3 are for pdfLaTeX.
6. Change one element with setbeamerfont
setbeamerfont{frametitle}{size=large,series=bfseries}The attributes are size, shape, series and family. Use usebeamerfont{name} to apply an element font inside your own template code.
Output and how to read it
Compile and inspect the frame title, body text and an equation separately: the three layers affect them differently. A serif theme changes text and, unless you use one of the stillsansserif options, math; a family package changes glyph shapes everywhere the package covers; setbeamerfont changes only the named element. In math, mathrm gives upright serif and mathsf sans-serif; operatorname adapts to the active setting.
Troubleshooting
The element font does not reset when I call setbeamerfont again
Calls to setbeamerfont accumulate: attributes you do not mention keep their earlier values. The guide’s example sets the title to shape=itshape,family=rmfamily and the title stays large because that size was set earlier. Use the starred form setbeamerfont* to reset the element first.
My math font package is ignored or the math glyphs look replaced
Beamer replaces some glyphs internally. usefonttheme{professionalfonts} suppresses that. It is switched on automatically, so you do not need to add it, when any of these are loaded: arevmath, hvmath, kpfonts, lmodern, lucidabr, lucimatx, mathastext, mathpmnt, mathpple, mathtime, mtpro, mtpro2 or unicode-math.
A font size option is rejected
8pt, 9pt, 14pt, 17pt and 20pt need extsizes. Without it, use 10pt, 11pt or 12pt.
Font themes change nothing about the family
A font theme only controls sans-serif or serif behaviour and structure emphasis; install a package for a different family.
Free alternatives
| Approach | Works with | Use when |
|---|---|---|
Font packages (mathptmx, helvet, lmodern, and so on) |
pdfLaTeX | You want a classic family from the guide’s list |
fontspec with system OpenType fonts |
LuaLaTeX, XeLaTeX | You need a font installed on your system or a template requires one |
setbeamerfont |
All engines | You only need to restyle individual elements |
All three are part of the TeX ecosystem and distributed through CTAN; this guide does not cover pricing of any editor.
Related CASRAI guides
- LaTeX boldface: bold text and bold math
- Spacing in LaTeX
- LaTeX notes template and preamble
- Writing LaTeX collaboratively in Overleaf
FAQ
How do I change the font in a Beamer presentation?
Load a font package in the preamble, for example usepackage{mathptmx} with usepackage{helvet}, or use fontspec under LuaLaTeX or XeLaTeX. Add usefonttheme{serif} if you want serif text.
Why is Beamer text sans serif?
The default font theme installs sans-serif for all text. usefonttheme{serif} changes this.
How do I change the font size?
Use a class option such as [12pt], or [17pt] with extsizes, for the whole presentation; use setbeamerfont{...}{size=...} for a single element.
How do I change only the frame title font?
setbeamerfont{frametitle}{size=large,series=bfseries}, changing the attributes you need.
Sources (official docs)
- Beamer User Guide v3.78, chapter 18 Fonts, read 2026-11-07: mirrors.ctan.org/macros/latex/contrib/beamer/doc/beameruserguide.pdf
- fontspec package documentation, read 2026-11-07: mirrors.ctan.org/macros/unicodetex/latex/fontspec/fontspec.pdf
