A variable font file contains data for an entire typeface family and allows an unlimited number of style variations along one or more design axes.

It uses interpolation, so designers only need to draw key masters to automatically visualize and/or generate intermediate instances.

HISTORY

The concept began with Apple’s TrueType GX technology for QuickDraw GX. Adobe, Google, and Microsoft later developed it into the OpenType Variable Font format, officially announced in 2016. Today, variable fonts are widely used in digital media, especially for responsive and animated text.

BENEFITS

Unlike static fonts, where each file contains a single style, a variable font can generate any style between its masters using interpolation. This reduces the number of separate files needed, decreases overall file size, and allows precise control over weight, width, slant, or other axes. Users can install one variable font file and dynamically adjust styles in applications or responsive environments without switching files.

FONT ENGINEERING HINT

Variable fonts store one full master (the origin) and delta data describing other masters. The gvar (Glyph Variation) table is the heart of outline interpolation. Tables like cvar, MVAR, HVAR, and VVAR handle metrics, spacing, and alignment changes across the axes. FVAR, AVAR, and STAT define, normalize, and provide human-readable names for the variation axes and their instances.