The TeX Catalogue OnLine, Entry for scalefnt, Ctan Edition

Rescale fonts to arbitrary sizes.

\scalefont{2} selects the current font in twice the current size. \scalefont{.75} reduces the current font size by three quarters.

Note that the effectiveness of such operations depends on the LaTeX font selection for that font; it will typically work well for ordinary Type 1 fonts, but Metafont fonts are usually set up to work only at a discrete set of sizes.

The author is David Carlisle.